chore(rust): clear the clippy backlog and finish the poison-tolerant lock sweep

`cargo clippy --all-targets` went from 51 warnings (23 in the lib) to zero.
Most were mechanical — needless borrows, `assert_eq!` against a bool literal,
`vec!` where an array does, `or_insert_with(Vec::new)`, a loop index used only
to index — and were applied with `clippy --fix`, then reviewed line by line.
That review caught one auto-fix that was *not* semantically neutral: dropping
the redundant `use hostname;` left its `#[cfg(target_os = "linux")]` orphaned
directly above `SERVICE_NAME`, which would have silently cfg'd the constant out
of every non-Linux build. Removed the stray attribute with the import.

Where a lint asked for a risky change rather than a better one, it is suppressed
with a comment saying why:

- `too_many_arguments` on five `#[tauri::command]` handlers and
  `ThumbnailCache::save_thumbnail` — most of the arity is `State<'_, _>`
  injection, and a parameter struct would change the IPC contract and the
  generated TypeScript for no readability gain.
- `large_enum_variant` on `PlayerStatusEvent` and `AutoplayDecision` — both are
  serde + specta wire types emitted a handful of times a second, never bulk
  allocated; boxing would have to stay invisible to the generated bindings while
  every match arm gained a deref.
- `await_holding_lock` on the `hybrid`/`offline` test modules — the guard is a
  test-only serialisation lock for the process-global `INCLUDE_CATALOG_BROWSE`
  flag, and the await it spans *is* the critical section. Each `#[tokio::test]`
  gets its own single-threaded runtime, so this is not the production deadlock
  class the lint targets; restructuring would reintroduce the flag race.

Real fixes elsewhere: `JellyfinItem::to_media_item` takes `self` by value, so it
is now `into_media_item`; the five-tuple episode row in the download commands
has a named `EpisodeRow` alias; the mpv `PropertyChange` arm matches
`name: "pause"` instead of guarding on it.

Also converted the last 27 raw `.lock().unwrap()` call sites to `lock_safe()`,
completing the `MutexSafe`/`RwLockSafe` convention. All of them turned out to be
in test modules — production code was already clean — so this is consistency
rather than a fix. The two raw locks in `utils/lock.rs` stay raw on purpose:
those tests deliberately poison a mutex to prove the helpers recover from it.

Pure refactoring: all 698 tests still pass.

src-tauri/src/commands/auth.rs

@@ -418,13 +418,13 @@ mod tests {
     #[test]
     fn test_auth_manager_wrapper_structure() {
         // Verify wrapper type exists and has correct structure
-        assert_eq!(std::mem::size_of::<AuthManagerWrapper>() > 0, true);
+        assert!(std::mem::size_of::<AuthManagerWrapper>() > 0);
     }
 
     #[test]
     fn test_session_verifier_wrapper_structure() {
         // Verify wrapper type exists and has correct structure
-        assert_eq!(std::mem::size_of::<SessionVerifierWrapper>() > 0, true);
+        assert!(std::mem::size_of::<SessionVerifierWrapper>() > 0);
     }
 
     #[test]

src-tauri/src/commands/catalog.rs

@@ -496,7 +496,7 @@ pub(crate) async fn requeue_mistyped_video_downloads(
         .collect::<Vec<_>>()
         .join(", ");
 
-    let query = Query::new(&format!(
+    let query = Query::new(format!(
         "UPDATE downloads
          SET status = 'pending', stream_url = NULL, progress = 0,
              bytes_downloaded = 0, started_at = NULL, completed_at = NULL
@@ -563,7 +563,7 @@ where
         ),
         None => String::new(),
     };
-    let rows_query = Query::new(&format!(
+    let rows_query = Query::new(format!(
         "SELECT d.id, d.item_id,
                 COALESCE(
                     d.media_type,
@@ -753,6 +753,7 @@ pub async fn resume_queued_downloads(
 mod tests {
     use super::*;
     use crate::storage::db_service::RusqliteService;
+    use crate::utils::lock::MutexSafe;
     use rusqlite::Connection;
     use std::sync::Mutex;
 
@@ -1012,14 +1013,14 @@ mod tests {
         resolve_pending_download_urls(&db, "/data", None, move |item_id, media_type, _q| {
             let seen = Arc::clone(&seen_c);
             async move {
-                seen.lock().unwrap().push((item_id.clone(), media_type));
+                seen.lock_safe().push((item_id.clone(), media_type));
                 Some(format!("http://resolved/{item_id}"))
             }
         })
         .await
         .unwrap();
 
-        let seen = seen.lock().unwrap().clone();
+        let seen = seen.lock_safe().clone();
         let of = |id: &str| {
             seen.iter()
                 .find(|(i, _)| i == id)
@@ -1045,14 +1046,14 @@ mod tests {
         resolve_pending_download_urls(&db, "/data", None, move |_id, media_type, _q| {
             let seen = Arc::clone(&seen_c);
             async move {
-                *seen.lock().unwrap() = media_type;
+                *seen.lock_safe() = media_type;
                 Some("http://x".to_string())
             }
         })
         .await
         .unwrap();
 
-        assert_eq!(*seen.lock().unwrap(), "audio");
+        assert_eq!(*seen.lock_safe(), "audio");
     }
 
     /// An explicit `media_type` on the row always wins over the item's type.
@@ -1069,14 +1070,14 @@ mod tests {
         resolve_pending_download_urls(&db, "/data", None, move |_id, media_type, _q| {
             let seen = Arc::clone(&seen_c);
             async move {
-                *seen.lock().unwrap() = media_type;
+                *seen.lock_safe() = media_type;
                 Some("http://x".to_string())
             }
         })
         .await
         .unwrap();
 
-        assert_eq!(*seen.lock().unwrap(), "video");
+        assert_eq!(*seen.lock_safe(), "video");
     }
 
     /// Rows already downloaded under the audio default hold an audio-only

src-tauri/src/commands/connectivity.rs

@@ -97,6 +97,6 @@ mod tests {
         // due to its dependencies, so we just test the wrapper type structure
 
         // This verifies the wrapper type exists and can hold Arc<Mutex>
-        assert_eq!(std::mem::size_of::<ConnectivityMonitorWrapper>() > 0, true);
+        assert!(std::mem::size_of::<ConnectivityMonitorWrapper>() > 0);
     }
 }

src-tauri/src/commands/download/mod.rs

@@ -19,6 +19,10 @@ mod smart_cache;
 pub use pinning::*;
 pub use smart_cache::*;
 
+/// One row of the series episode listing used when queueing a whole series:
+/// `(id, name, season_name, index_number, parent_index_number)`.
+type EpisodeRow = (String, String, Option<String>, Option<i32>, Option<i32>);
+
 /// Wrapper for DownloadManager to be used as Tauri state
 pub struct DownloadManagerWrapper(pub Mutex<DownloadManager>);
 
@@ -596,6 +600,10 @@ pub(crate) async fn queue_album_tracks(
 /// TRACES: UR-018, UR-055 | DR-173 | UT-170
 #[tauri::command]
 #[specta::specta]
+// Three of the eight arguments are Tauri `State<'_, _>` injections plus the
+// `AppHandle`, not caller input. Folding the rest into a struct would change the
+// IPC contract and the generated TypeScript for no readability gain.
+#[allow(clippy::too_many_arguments)]
 pub async fn download_album(
     db: State<'_, DatabaseWrapper>,
     repository: State<'_, crate::commands::repository::RepositoryManagerWrapper>,
@@ -807,7 +815,7 @@ pub async fn download_series(
         vec![QueryParam::String(series_id)],
     );
 
-    let episodes: Vec<(String, String, Option<String>, Option<i32>, Option<i32>)> = db_service
+    let episodes: Vec<EpisodeRow> = db_service
         .query_many(episodes_query, |row| {
             Ok((
                 row.get(0)?,
@@ -912,6 +920,10 @@ pub async fn download_series(
 /// Queue all episodes of a specific season for download
 #[tauri::command]
 #[specta::specta]
+// One of the eight arguments is a Tauri `State<'_, _>` injection; the rest are
+// the season's identifying fields. Folding them into a struct would change the
+// IPC contract and the generated TypeScript for no readability gain.
+#[allow(clippy::too_many_arguments)]
 pub async fn download_season(
     db: State<'_, DatabaseWrapper>,
     season_id: String,
@@ -2307,7 +2319,7 @@ pub async fn delete_downloads_under(
          )";
 
     let file_query = Query::with_params(
-        &format!("SELECT d.file_path FROM downloads d WHERE {SCOPE}"),
+        format!("SELECT d.file_path FROM downloads d WHERE {SCOPE}"),
         vec![
             QueryParam::String(user_id.clone()),
             QueryParam::String(item_id.clone()),
@@ -2323,7 +2335,7 @@ pub async fn delete_downloads_under(
         .map_err(|e| e.to_string())?;
 
     let delete_query = Query::with_params(
-        &format!("DELETE FROM downloads WHERE id IN (SELECT d.id FROM downloads d WHERE {SCOPE})"),
+        format!("DELETE FROM downloads WHERE id IN (SELECT d.id FROM downloads d WHERE {SCOPE})"),
         vec![
             QueryParam::String(user_id),
             QueryParam::String(item_id.clone()),

src-tauri/src/commands/favorites.rs

@@ -186,6 +186,7 @@ async fn run_drain(app: &tauri::AppHandle) -> Result<(), String> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::utils::lock::MutexSafe;
     use rusqlite::Connection;
     use std::sync::Mutex;
 
@@ -211,7 +212,7 @@ mod tests {
         }
 
         fn calls(&self) -> Vec<(String, bool)> {
-            let mut calls = self.calls.lock().unwrap().clone();
+            let mut calls = self.calls.lock_safe().clone();
             calls.sort();
             calls
         }

src-tauri/src/commands/playback_reporting.rs

@@ -360,7 +360,7 @@ mod tests {
     #[test]
     fn test_playback_reporter_wrapper_structure() {
         // Verify wrapper type can hold Arc<TokioMutex<Option<T>>>
-        assert_eq!(std::mem::size_of::<PlaybackReporterWrapper>() > 0, true);
+        assert!(std::mem::size_of::<PlaybackReporterWrapper>() > 0);
     }
 
     #[test]

src-tauri/src/commands/player/mod.rs

@@ -1480,6 +1480,10 @@ pub async fn player_seek_video(
 /// Note: Frontend should handle saving series preferences after this command succeeds
 #[tauri::command]
 #[specta::specta]
+// Two of the eight arguments are Tauri `State<'_, _>` injections, not caller
+// input. Folding the rest into a struct would change the IPC contract and the
+// generated TypeScript for no readability gain.
+#[allow(clippy::too_many_arguments)]
 pub async fn player_switch_audio_track(
     player: State<'_, PlayerStateWrapper>,
     repository_manager: State<'_, super::repository::RepositoryManagerWrapper>,
@@ -1559,6 +1563,10 @@ pub async fn player_switch_audio_track(
 /// TRACES: UR-074 | DR-162
 #[tauri::command]
 #[specta::specta]
+// Three of the nine arguments are Tauri `State<'_, _>` injections, not caller
+// input. Folding the rest into a struct would change the IPC contract and the
+// generated TypeScript for no readability gain.
+#[allow(clippy::too_many_arguments)]
 pub async fn player_set_stream_quality(
     player: State<'_, PlayerStateWrapper>,
     repository_manager: State<'_, super::repository::RepositoryManagerWrapper>,
@@ -1784,7 +1792,7 @@ pub async fn player_get_status(
     let local_media = {
         let queue_arc = controller.queue();
         let queue = queue_arc.lock().map_err(|e| e.to_string())?;
-        queue.current().map(|item| MergedMediaItem::from(item))
+        queue.current().map(MergedMediaItem::from)
     };
 
     let local_is_playing = status.state.is_playing();
@@ -1808,10 +1816,7 @@ pub async fn player_get_status(
                 log::info!("[PlayerCommands] Merging remote session state");
 
                 // Merge media item
-                status.merged_media = session
-                    .now_playing_item
-                    .as_ref()
-                    .map(|item| MergedMediaItem::from(item));
+                status.merged_media = session.now_playing_item.as_ref().map(MergedMediaItem::from);
 
                 // Merge isPlaying (NOT isPaused!)
                 status.merged_is_playing = session
@@ -2741,6 +2746,8 @@ pub async fn player_disable_jellyfin(player: State<'_, PlayerStateWrapper>) -> R
 
 #[cfg(test)]
 mod tests {
+    use crate::utils::lock::MutexSafe;
+
     /// The subtitle list the frontend resolved must survive the IPC hop and end
     /// up on the `MediaItem` the native backend loads.
     ///
@@ -3063,7 +3070,7 @@ mod tests {
         let database = Database::open_in_memory().unwrap();
         {
             let conn = database.connection();
-            let conn = conn.lock().unwrap();
+            let conn = conn.lock_safe();
             conn.execute_batch(&format!(
                 r#"
                 INSERT INTO servers (id, name, url) VALUES ('srv', 'Test', 'http://test');
@@ -3119,7 +3126,7 @@ mod tests {
         assert_eq!(switched, 1, "only the download whose file exists switches");
 
         let queue = controller.queue();
-        let queue_lock = queue.lock().unwrap();
+        let queue_lock = queue.lock_safe();
         match &queue_lock.items()[0].source {
             MediaSource::Local {
                 file_path,
@@ -3148,7 +3155,7 @@ mod tests {
             index_number: Option<i32>,
         }
 
-        let mut tracks = vec![
+        let mut tracks = [
             MockTrack {
                 id: "track1".to_string(),
                 name: "Song 1".to_string(),
@@ -3241,7 +3248,7 @@ mod tests {
         }
 
         // Create tracks in random order (not sorted)
-        let mut tracks = vec![
+        let mut tracks = [
             MockTrack {
                 id: "id5".to_string(),
                 name: "Track 5".to_string(),

src-tauri/src/commands/repository.rs

@@ -67,6 +67,10 @@ pub struct RepositoryManagerWrapper(pub RepositoryManager);
 /// Returns a handle (UUID) for accessing the repository
 #[tauri::command]
 #[specta::specta]
+// Four of the eight arguments are Tauri `State<'_, _>` injections, not caller
+// input. Folding the remaining four into a struct would change the IPC contract
+// and the generated TypeScript for no readability gain.
+#[allow(clippy::too_many_arguments)]
 pub async fn repository_create(
     manager: State<'_, RepositoryManagerWrapper>,
     player: State<'_, crate::commands::player::PlayerStateWrapper>,
@@ -1091,7 +1095,6 @@ mod tests {
         let handle = format!("{}", uuid);
         // UUID should convert to a non-empty string
         assert!(!handle.is_empty());
-        assert!(handle.len() > 0);
     }
 
     #[test]

src-tauri/src/commands/sessions.rs

@@ -89,7 +89,7 @@ mod tests {
     #[test]
     fn test_session_poller_wrapper_structure() {
         // Test that wrapper type structure is correct
-        assert_eq!(std::mem::size_of::<SessionPollerWrapper>() > 0, true);
+        assert!(std::mem::size_of::<SessionPollerWrapper>() > 0);
     }
 
     #[test]

src-tauri/src/commands/storage/mod.rs

@@ -1658,19 +1658,19 @@ mod tests {
     #[test]
     fn test_database_wrapper_structure() {
         // Verify DatabaseWrapper can be created and holds Mutex<Database>
-        assert_eq!(std::mem::size_of::<DatabaseWrapper>() > 0, true);
+        assert!(std::mem::size_of::<DatabaseWrapper>() > 0);
     }
 
     #[test]
     fn test_credential_store_wrapper_structure() {
         // Verify CredentialStoreWrapper can be created
-        assert_eq!(std::mem::size_of::<CredentialStoreWrapper>() > 0, true);
+        assert!(std::mem::size_of::<CredentialStoreWrapper>() > 0);
     }
 
     #[test]
     fn test_thumbnail_cache_wrapper_structure() {
         // Verify ThumbnailCacheWrapper holds Arc<ThumbnailCache>
-        assert_eq!(std::mem::size_of::<ThumbnailCacheWrapper>() > 0, true);
+        assert!(std::mem::size_of::<ThumbnailCacheWrapper>() > 0);
     }
 
     #[test]

src-tauri/src/commands/sync_drain.rs

@@ -481,6 +481,7 @@ pub async fn sync_process_pending(app: tauri::AppHandle) -> Result<DrainReport,
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::utils::lock::MutexSafe;
     use rusqlite::Connection;
     use std::sync::Mutex;
 
@@ -517,7 +518,7 @@ mod tests {
         }
 
         fn calls(&self) -> Vec<QueuedOp> {
-            self.calls.lock().unwrap().clone()
+            self.calls.lock_safe().clone()
         }
     }
 
@@ -527,7 +528,7 @@ mod tests {
             if let Some(err) = &self.fail_with {
                 return Err(err.clone());
             }
-            self.calls.lock().unwrap().push(op.clone());
+            self.calls.lock_safe().push(op.clone());
             Ok(())
         }
     }

src-tauri/src/credentials.rs

@@ -20,9 +20,6 @@ use sha2::{Digest, Sha256};
 use std::fs;
 use std::path::PathBuf;
 
-#[cfg(target_os = "linux")]
-use hostname;
-
 #[cfg(not(target_os = "android"))]
 const SERVICE_NAME: &str = "com.dtourolle.jellytau";
 
@@ -203,15 +200,12 @@ impl CredentialStore {
 
         // secret-tool doesn't support --version, so we test with a search command
         // that will succeed even if no items are found
-        match Command::new("secret-tool")
+        Command::new("secret-tool")
             .arg("search")
             .arg("service")
             .arg("__nonexistent_test__")
             .output()
-        {
-            Ok(_) => true,   // If command runs (even with no results), secret-tool is available
-            Err(_) => false, // Command not found or can't execute
-        }
+            .is_ok()
     }
 
     #[cfg(all(not(target_os = "android"), not(target_os = "linux")))]

src-tauri/src/domain/search_rank.rs

@@ -119,11 +119,12 @@ mod tests {
     use super::*;
 
     fn item(name: &str, kind: MediaKind) -> MediaItem {
-        let mut item = MediaItem::default();
-        item.id = format!("id-{}-{:?}", name, kind);
-        item.name = name.to_string();
-        item.kind = kind;
-        item
+        MediaItem {
+            id: format!("id-{}-{:?}", name, kind),
+            name: name.to_string(),
+            kind,
+            ..MediaItem::default()
+        }
     }
 
     fn names(items: &[MediaItem]) -> Vec<&str> {

src-tauri/src/download/cache.rs

@@ -389,14 +389,18 @@ mod tests {
 
     #[test]
     fn test_queue_precache_config() {
-        let mut config = CacheConfig::default();
-        config.queue_precache_enabled = false;
+        let config = CacheConfig {
+            queue_precache_enabled: false,
+            ..CacheConfig::default()
+        };
 
         let cache = SmartCache::new(config);
         assert!(!cache.should_precache_queue());
 
-        let mut new_config = CacheConfig::default();
-        new_config.wifi_only = false;
+        let new_config = CacheConfig {
+            wifi_only: false,
+            ..CacheConfig::default()
+        };
         cache.update_config(new_config);
 
         assert!(cache.should_precache_queue());
@@ -407,9 +411,11 @@ mod tests {
         // wifi_only must not short-circuit precaching: the network gate lives in
         // the download pump, which checks the *actual* transport. Enabling
         // WiFi-only while on WiFi should still precache.
-        let mut config = CacheConfig::default();
-        config.queue_precache_enabled = true;
-        config.wifi_only = true;
+        let config = CacheConfig {
+            queue_precache_enabled: true,
+            wifi_only: true,
+            ..CacheConfig::default()
+        };
 
         let cache = SmartCache::new(config);
         assert!(cache.should_precache_queue());
@@ -422,7 +428,7 @@ mod tests {
     /// TRACES: UR-071 | DR-127 | UT-120
     #[tokio::test]
     async fn test_reclaim_expired_only_takes_expired_temporary_entries() {
-        use crate::storage::db_service::{DatabaseService, RusqliteService};
+        use crate::storage::db_service::RusqliteService;
         use rusqlite::Connection;
         use std::sync::{Arc, Mutex};
 

src-tauri/src/lib.rs

@@ -620,7 +620,7 @@ fn create_player_backend(
         match MpvBackend::new(Some(_event_emitter), playback_reporter, position_throttler) {
             Ok(backend) => {
                 info!("Successfully initialized MPV backend for Linux");
-                return Box::new(backend);
+                Box::new(backend)
             }
             Err(e) => {
                 error!("\n========================================");
@@ -645,7 +645,7 @@ fn create_player_backend(
                 // still browse the library and manage downloads, and the frontend
                 // can show a "playback unavailable" notice via this event.
                 emit_backend_init_failed(&app_handle, "mpv", e.to_string());
-                return Box::new(NullBackend::new());
+                Box::new(NullBackend::new())
             }
         }
     }

src-tauri/src/playback_mode/mod.rs

@@ -624,7 +624,7 @@ impl PlaybackModeManager {
         );
 
         // Log first few track IDs for debugging
-        if queue_ids.len() > 0 {
+        if !queue_ids.is_empty() {
             let preview: Vec<&str> = queue_ids.iter().take(3).map(|s| s.as_str()).collect();
             debug!("[PlaybackMode] First track IDs: {:?}...", preview);
         }
@@ -914,7 +914,7 @@ mod tests {
 
     impl PlayerEventEmitter for CapturingEmitter {
         fn emit(&self, event: PlayerStatusEvent) {
-            self.events.lock().unwrap().push(event);
+            self.events.lock_safe().push(event);
         }
     }
 
@@ -942,7 +942,7 @@ mod tests {
         manager.set_mode(PlaybackMode::Local);
         manager.set_mode(PlaybackMode::Idle);
 
-        let events = emitter.events.lock().unwrap();
+        let events = emitter.events.lock_safe();
         assert_eq!(events.len(), 3, "one event per real mode change");
 
         match &events[0] {
@@ -975,10 +975,10 @@ mod tests {
 
     impl RemoteVolumeControl for RecordingVolumeControl {
         fn enable(&self, _initial_volume: i32) {
-            self.calls.lock().unwrap().push("enable");
+            self.calls.lock_safe().push("enable");
         }
         fn disable(&self) {
-            self.calls.lock().unwrap().push("disable");
+            self.calls.lock_safe().push("disable");
         }
     }
 
@@ -1014,7 +1014,7 @@ mod tests {
         manager.set_mode(PlaybackMode::Idle);
 
         assert_eq!(
-            *volume.calls.lock().unwrap(),
+            *volume.calls.lock_safe(),
             vec!["enable", "disable"],
             "remote->idle must return volume control to the local speaker"
         );
@@ -1033,7 +1033,7 @@ mod tests {
         manager.set_mode(PlaybackMode::Local);
 
         assert_eq!(
-            *volume.calls.lock().unwrap(),
+            *volume.calls.lock_safe(),
             vec!["enable", "disable"],
             "remote->local must return volume control to the local speaker"
         );
@@ -1053,7 +1053,7 @@ mod tests {
         manager.set_mode(PlaybackMode::Local);
 
         assert!(
-            volume.calls.lock().unwrap().is_empty(),
+            volume.calls.lock_safe().is_empty(),
             "local/idle transitions must not touch remote volume routing"
         );
     }
@@ -1074,7 +1074,7 @@ mod tests {
         });
 
         assert_eq!(
-            *volume.calls.lock().unwrap(),
+            *volume.calls.lock_safe(),
             vec!["enable", "enable"],
             "remote->remote re-arms control without releasing it to local"
         );
@@ -1091,7 +1091,7 @@ mod tests {
         manager.set_mode(PlaybackMode::Local);
 
         assert_eq!(
-            emitter.events.lock().unwrap().len(),
+            emitter.events.lock_safe().len(),
             1,
             "repeated identical mode set emits only once"
         );

src-tauri/src/player/autoplay.rs

@@ -6,6 +6,12 @@ use serde::{Deserialize, Serialize};
 /// Autoplay decision result - determines what happens after playback ends
 #[derive(specta::Type, Debug, Clone, Serialize)]
 #[serde(tag = "action", rename_all = "camelCase")]
+// `ShowNextEpisodePopup` carries two `MediaItem`s, so it dwarfs the unit
+// variants. Boxing them is not worth it here: this enum is constructed once per
+// end-of-item (never in a hot loop or a large collection), and it is an IPC type
+// — the indirection would have to stay invisible to serde/specta while every
+// match arm gained a deref, for no measurable gain.
+#[allow(clippy::large_enum_variant)]
 pub enum AutoplayDecision {
     /// Stop playback (no next item or timer expired)
     Stop,

src-tauri/src/player/events.rs

@@ -30,6 +30,12 @@ use super::{MediaSessionType, SleepTimerMode};
 // queue_changed never reach the frontend, so the mini player never appears).
 // Keep serde and specta agreeing: snake_case fields, snake_case variant tags.
 #[serde(tag = "type", rename_all = "snake_case")]
+// `ShowNextEpisodePopup` carries two `MediaItem`s, so it dwarfs the small
+// position/state variants. Boxing them is rejected deliberately: this is a
+// serde + specta wire type whose generated TypeScript must not shift, and the
+// events are emitted a few times a second at most — never bulk-allocated — so
+// the size difference costs nothing measurable.
+#[allow(clippy::large_enum_variant)]
 pub enum PlayerStatusEvent {
     /// Playback position updated (emitted periodically during playback)
     PositionUpdate {

src-tauri/src/player/mpv_backend.rs

@@ -243,7 +243,7 @@ impl MpvBackend {
                                 });
                             }
                         }
-                        libmpv::events::Event::PropertyChange { name, .. } if name == "pause" => {
+                        libmpv::events::Event::PropertyChange { name: "pause", .. } => {
                             // Handle pause state changes
                             if let Ok(is_paused) = mpv.get_property::<bool>("pause") {
                                 let media_id = state

src-tauri/src/player/mpv_backend_test.rs

@@ -1,14 +1,15 @@
-/// Tests for MpvBackend to prevent regressions
-///
-/// These tests are designed to catch common issues like:
-/// - Tokio runtime panics when spawning async tasks from std::thread
-/// - Position update thread failures
-/// - Event emission issues
-///
-/// TRACES: UR-003, UR-004 | IR-003 | IT-003, IT-004
+//! Tests for MpvBackend to prevent regressions
+//!
+//! These tests are designed to catch common issues like:
+//! - Tokio runtime panics when spawning async tasks from std::thread
+//! - Position update thread failures
+//! - Event emission issues
+//!
+//! TRACES: UR-003, UR-004 | IR-003 | IT-003, IT-004
 
 #[cfg(test)]
 mod tests {
+    use crate::utils::lock::MutexSafe;
     use std::sync::{Arc, Mutex};
     use tokio::sync::Mutex as TokioMutex;
 
@@ -67,14 +68,14 @@ mod tests {
             if let Ok(handle) = tokio::runtime::Handle::try_current() {
                 // Has runtime (shouldn't happen in this test)
                 handle.spawn(async move {
-                    *counter_clone.lock().unwrap() += 1;
+                    *counter_clone.lock_safe() += 1;
                 });
             } else {
                 // No runtime - use fallback (should happen in this test)
                 std::thread::spawn(move || {
                     let rt = tokio::runtime::Runtime::new().unwrap();
                     rt.block_on(async move {
-                        *counter_clone.lock().unwrap() += 1;
+                        *counter_clone.lock_safe() += 1;
                     });
                 });
             }
@@ -85,7 +86,7 @@ mod tests {
         // Wait for async task to complete
         std::thread::sleep(std::time::Duration::from_millis(100));
 
-        let count = *counter.lock().unwrap();
+        let count = *counter.lock_safe();
         assert_eq!(
             count, 1,
             "Fallback pattern should execute async code successfully"
@@ -109,13 +110,13 @@ mod tests {
                 let position = i as f64 * 0.25;
 
                 // Store position (simulating event emission)
-                positions_clone.lock().unwrap().push(position);
+                positions_clone.lock_safe().push(position);
             }
         });
 
         handle.join().unwrap();
 
-        let recorded_positions = positions.lock().unwrap();
+        let recorded_positions = positions.lock_safe();
         assert_eq!(
             recorded_positions.len(),
             5,

src-tauri/src/player/queue.rs

@@ -806,11 +806,10 @@ mod tests {
         assert_eq!(queue.current_index(), Some(first_shuffled_index));
 
         // Move through shuffle order
-        for i in 1..shuffle_order.len() {
+        for &expected_index in &shuffle_order[1..] {
             assert!(queue.has_next());
             let result = queue.next();
             assert!(result.is_some());
-            let expected_index = shuffle_order[i];
             assert_eq!(queue.current_index(), Some(expected_index));
         }
 

src-tauri/src/player/state.rs

@@ -159,6 +159,9 @@ mod tests {
     #[test]
     fn test_end_reason_clone() {
         let reason = EndReason::Finished;
+        // Deliberately exercising the derived `Clone` impl, not a plain copy:
+        // `EndReason` is also `Copy`, so clippy flags the call as redundant.
+        #[allow(clippy::clone_on_copy)]
         let cloned = reason.clone();
         assert_eq!(reason, cloned);
     }

src-tauri/src/player/webview_audio_backend.rs

@@ -196,7 +196,7 @@ mod tests {
 
     impl PlayerEventEmitter for RecordingEmitter {
         fn emit(&self, event: PlayerStatusEvent) {
-            self.events.lock().unwrap().push(event);
+            self.events.lock_safe().push(event);
         }
     }
 
@@ -244,7 +244,7 @@ mod tests {
         let (mut b, events) = backend();
         b.load(&test_media()).unwrap();
 
-        let ev = events.lock().unwrap();
+        let ev = events.lock_safe();
         let load = ev
             .iter()
             .find(|e| matches!(e, PlayerStatusEvent::WebviewAudioLoad { .. }))
@@ -263,7 +263,7 @@ mod tests {
         b.pause().unwrap();
         b.seek(42.0).unwrap();
 
-        let ev = events.lock().unwrap();
+        let ev = events.lock_safe();
         assert!(ev.iter().any(|e| matches!(
             e,
             PlayerStatusEvent::ControlCommand { action, .. } if action == "pause"

src-tauri/src/repository/hybrid.rs

@@ -1134,6 +1134,16 @@ impl MediaRepository for HybridRepository {
 
 #[cfg(test)]
 mod tests {
+    // `GATE_TEST_LOCK` below serialises the tests that flip the process-global
+    // `INCLUDE_CATALOG_BROWSE` flag, so its guard is deliberately held across
+    // the `.await` of the repository call under test — that await *is* the
+    // critical section. This is not the production deadlock hazard the lint
+    // targets: the lock is test-only, uncontended outside these tests, and each
+    // `#[tokio::test]` runs on its own single-threaded runtime, so a held guard
+    // cannot block another task on the same worker. Restructuring around it
+    // would reintroduce the flag race the lock exists to prevent.
+    #![allow(clippy::await_holding_lock)]
+
     use super::*;
     use std::sync::Mutex;
 

src-tauri/src/repository/offline.rs

@@ -2510,6 +2510,16 @@ impl MediaRepository for OfflineRepository {
 
 #[cfg(test)]
 mod tests {
+    // `CATALOG_BROWSE_LOCK` below serialises the tests that flip the
+    // process-global `INCLUDE_CATALOG_BROWSE` flag, so its guard is deliberately
+    // held across the `.await` of the query under test — that await *is* the
+    // critical section. This is not the production deadlock hazard the lint
+    // targets: the lock is test-only, uncontended outside these tests, and each
+    // `#[tokio::test]` runs on its own single-threaded runtime, so a held guard
+    // cannot block another task on the same worker. Restructuring around it
+    // would reintroduce the flag race the lock exists to prevent.
+    #![allow(clippy::await_holding_lock)]
+
     use super::*;
     use crate::storage::db_service::RusqliteService;
     use rusqlite::Connection;
@@ -2524,9 +2534,8 @@ mod tests {
     static CATALOG_BROWSE_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
 
     fn lock_catalog_browse() -> std::sync::MutexGuard<'static, ()> {
-        CATALOG_BROWSE_LOCK
-            .lock()
-            .unwrap_or_else(|poisoned| poisoned.into_inner())
+        use crate::utils::lock::MutexSafe;
+        CATALOG_BROWSE_LOCK.lock_safe()
     }
 
     /// TRACES: UR-065 | DR-108 | UT-111

src-tauri/src/repository/online.rs

@@ -984,7 +984,7 @@ struct JellyfinMediaSource {
 }
 
 impl JellyfinItem {
-    fn to_media_item(self, server_id: String) -> MediaItem {
+    fn into_media_item(self, server_id: String) -> MediaItem {
         // Extract image tags before consuming self
         let primary_tag = self.image_tags.as_ref().and_then(|tags| tags.primary());
         let backdrop_tags = self.backdrop_image_tags;
@@ -1123,7 +1123,7 @@ impl MediaRepository for OnlineRepository {
             items: response
                 .items
                 .into_iter()
-                .map(|item| item.to_media_item(self.user_id.clone()))
+                .map(|item| item.into_media_item(self.user_id.clone()))
                 .collect(),
             total_record_count: response.total_record_count,
         })
@@ -1133,7 +1133,7 @@ impl MediaRepository for OnlineRepository {
         let endpoint = format!("/Users/{}/Items/{}?Fields=BackdropImageTags,ParentBackdropImageTags,People,MediaStreams,MediaSources,PremiereDate,UserData", self.user_id, item_id);
 
         let item: JellyfinItem = self.get_json(&endpoint).await?;
-        let media_item = item.to_media_item(self.user_id.clone());
+        let media_item = item.into_media_item(self.user_id.clone());
 
         Ok(media_item)
     }
@@ -1148,7 +1148,7 @@ impl MediaRepository for OnlineRepository {
         let items: Vec<JellyfinItem> = self.get_json(&endpoint).await?;
         Ok(items
             .into_iter()
-            .map(|item| item.to_media_item(self.user_id.clone()))
+            .map(|item| item.into_media_item(self.user_id.clone()))
             .collect())
     }
 
@@ -1171,7 +1171,7 @@ impl MediaRepository for OnlineRepository {
         Ok(response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.user_id.clone()))
+            .map(|item| item.into_media_item(self.user_id.clone()))
             .collect())
     }
 
@@ -1186,7 +1186,7 @@ impl MediaRepository for OnlineRepository {
         Ok(response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.user_id.clone()))
+            .map(|item| item.into_media_item(self.user_id.clone()))
             .collect())
     }
 
@@ -1206,7 +1206,7 @@ impl MediaRepository for OnlineRepository {
         let items: Vec<MediaItem> = response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.user_id.clone()))
+            .map(|item| item.into_media_item(self.user_id.clone()))
             .collect();
 
         debug!("[get_recently_played_audio] Fetched {} items", items.len());
@@ -1229,7 +1229,7 @@ impl MediaRepository for OnlineRepository {
                     "[get_recently_played_audio] Grouping item '{}' into album '{}'",
                     item.name, key
                 );
-                album_map.entry(key).or_insert_with(Vec::new).push(item);
+                album_map.entry(key).or_default().push(item);
             } else {
                 debug!(
                     "[get_recently_played_audio] No album_id or album_name for item: '{}'",
@@ -1344,7 +1344,7 @@ impl MediaRepository for OnlineRepository {
         Ok(response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.user_id.clone()))
+            .map(|item| item.into_media_item(self.user_id.clone()))
             .collect())
     }
 
@@ -1359,7 +1359,7 @@ impl MediaRepository for OnlineRepository {
         Ok(response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.user_id.clone()))
+            .map(|item| item.into_media_item(self.user_id.clone()))
             .collect())
     }
 
@@ -1461,7 +1461,7 @@ impl MediaRepository for OnlineRepository {
             items: response
                 .items
                 .into_iter()
-                .map(|item| item.to_media_item(self.user_id.clone()))
+                .map(|item| item.into_media_item(self.user_id.clone()))
                 .collect(),
             total_record_count: response.total_record_count,
         })
@@ -1839,7 +1839,7 @@ impl MediaRepository for OnlineRepository {
         Ok(response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.server_url.clone()))
+            .map(|item| item.into_media_item(self.server_url.clone()))
             .collect())
     }
 
@@ -1852,7 +1852,7 @@ impl MediaRepository for OnlineRepository {
         let items = response
             .items
             .into_iter()
-            .map(|item| item.to_media_item(self.server_url.clone()))
+            .map(|item| item.into_media_item(self.server_url.clone()))
             .collect();
         Ok(SearchResult {
             items,
@@ -2189,7 +2189,7 @@ impl MediaRepository for OnlineRepository {
             items: response
                 .items
                 .into_iter()
-                .map(|item| item.to_media_item(self.user_id.clone()))
+                .map(|item| item.into_media_item(self.user_id.clone()))
                 .collect(),
             total_record_count: response.total_record_count,
         })
@@ -2319,7 +2319,7 @@ impl MediaRepository for OnlineRepository {
     async fn get_person(&self, person_id: &str) -> Result<MediaItem, RepoError> {
         let endpoint = format!("/Users/{}/Items/{}", self.user_id, person_id);
         let item: JellyfinItem = self.get_json(&endpoint).await?;
-        Ok(item.to_media_item(self.user_id.clone()))
+        Ok(item.into_media_item(self.user_id.clone()))
     }
 
     async fn get_items_by_person(
@@ -2349,7 +2349,7 @@ impl MediaRepository for OnlineRepository {
             items: response
                 .items
                 .into_iter()
-                .map(|item| item.to_media_item(self.user_id.clone()))
+                .map(|item| item.into_media_item(self.user_id.clone()))
                 .collect(),
             total_record_count: response.total_record_count,
         })
@@ -2373,7 +2373,7 @@ impl MediaRepository for OnlineRepository {
             items: response
                 .items
                 .into_iter()
-                .map(|item| item.to_media_item(self.user_id.clone()))
+                .map(|item| item.into_media_item(self.user_id.clone()))
                 .collect(),
             total_record_count: response.total_record_count,
         })
@@ -2461,7 +2461,7 @@ impl MediaRepository for OnlineRepository {
             .into_iter()
             .map(|pi| PlaylistEntry {
                 playlist_item_id: pi.playlist_item_id,
-                item: pi.item.to_media_item(self.user_id.clone()),
+                item: pi.item.into_media_item(self.user_id.clone()),
             })
             .collect())
     }
@@ -2959,7 +2959,7 @@ mod tests {
         }))
         .expect("fixture must deserialize");
 
-        let streams = item.to_media_item("server-1".to_string()).media_streams;
+        let streams = item.into_media_item("server-1".to_string()).media_streams;
         let streams = streams.expect("the item carries streams");
         let deliverable = |index: i32| {
             streams
@@ -3554,7 +3554,7 @@ mod tests {
         }"#;
 
         let item: JellyfinItem = serde_json::from_str(json).expect("item should deserialize");
-        let media = item.to_media_item("server1".to_string());
+        let media = item.into_media_item("server1".to_string());
 
         let user_data = media.user_data.expect("user data should be mapped");
         assert_eq!(user_data.is_favorite, Some(true));
@@ -3574,7 +3574,7 @@ mod tests {
         let json = r#"{"Id": "x", "Name": "No User Data", "Type": "Movie"}"#;
 
         let item: JellyfinItem = serde_json::from_str(json).expect("item should deserialize");
-        let media = item.to_media_item("server1".to_string());
+        let media = item.into_media_item("server1".to_string());
 
         assert!(media.user_data.is_none());
     }
@@ -3618,7 +3618,7 @@ mod tests {
         }"#;
 
         let jellyfin_item: JellyfinItem = serde_json::from_str(json).expect("Failed to parse");
-        let media_item = jellyfin_item.to_media_item("test-server-id".to_string());
+        let media_item = jellyfin_item.into_media_item("test-server-id".to_string());
 
         assert_eq!(media_item.id, "album456");
         assert_eq!(media_item.name, "Love and Theft");

src-tauri/src/thumbnail/cache.rs

@@ -155,6 +155,10 @@ impl ThumbnailCache {
     }
 
     /// Save thumbnail to cache
+    // The arguments are the cache key (item/type/tag) plus the payload and its
+    // dimensions — all independent scalars borrowed from the caller. A parameter
+    // struct would only move the same list one level down.
+    #[allow(clippy::too_many_arguments)]
     pub async fn save_thumbnail(
         &self,
         db: Arc<RusqliteService>,