feat(offline): play downloaded video, and drain the offline sync queue (0.4.6)

Bundles this session's work plus the concurrent search/offline/player changes.
Every gate passes on the combined tree: 885 frontend tests, 610 Rust tests,
clippy clean, boundary clean, trace coverage 86%.

Offline video playback — four separate defects, each of which alone stopped it:

  DR-133  A completed download's file_path is already absolute (the worker
          rewrites it on completion), but the player rooted it a second time and
          handed the webview /data/user/0/app//data/user/0/app/videos/x.mp4.
  DR-134  The asset protocol was never enabled: no protocol-asset feature and no
          assetProtocol config, so convertFileSrc produced URLs nothing answered.
          Also silently defeated the cached-thumbnail path, which fails soft to
          the server copy and hid it whenever the server was reachable.
  DR-137  Tauri's asset protocol answers a range-less request by reading the
          whole file into memory, and only advertises Accept-Ranges from inside
          its range branch, so the first request never learns ranges exist.
          Chromium gave up with PIPELINE_ERROR_READ after ~31s. Local media is
          now served by a loopback HTTP server: bounded 4 MiB chunks streamed
          from the file handle, every response length-delimited, and a range-less
          request answered with one chunk rather than the file. Confined by a
          per-session token and to the app data directory, because loopback is
          shared between apps on Android.
  DR-138  Release builds set usesCleartextTraffic=false, so Android rejected the
          request to that server before any I/O. A network-security-config
          exempts 127.0.0.1 only; a remote server must still be HTTPS.

Downloads:

  DR-135  download_item never records media_type and the reconnect resolver read
          that NULL as 'audio', so a movie queued from a media card had its URL
          resolved by get_audio_stream_url and completed as an audio-only
          transcode. The item's own type now decides.
  DR-136  Rows already downloaded that way are requeued on reconnect, since
          prevention alone leaves them reading "downloaded" and still unplayable.

Known limitation: a download taken at `original` quality is a byte copy of the
source, so it can be any container. One such file is an AVI holding XVID, which
the webview cannot play in any case — the media server serves it correctly and
Chromium refuses it. That needs either a transcoded download preset or the
native ExoPlayer surface work, and is not addressed here.

Also fixes two ID collisions between concurrent work: DR-143 defined twice
(search vs offline gate) and UT-131 defined twice (Episode Focus hero vs channel
cap). The search requirement is now DR-147 and the channel-cap test UT-141, with
their code references and matrix rows updated.

src-tauri/src/commands/sync.rs

@@ -2,7 +2,9 @@
 //!
 //! The sync queue stores mutations (favorites, playback progress, etc.)
 //! that need to be synced to the Jellyfin server when connectivity is restored.
-//! TRACES: UR-002, UR-017, UR-025 | DR-014
+//! Draining it lives in `sync_drain` (DR-131); this module is the storage and
+//! read side the UI lists from (DR-132).
+//! TRACES: UR-002, UR-017, UR-025 | DR-014, DR-131, DR-132
 
 use serde::{Deserialize, Serialize};
 use std::sync::Arc;
@@ -24,6 +26,12 @@ pub struct SyncQueueItem {
     pub retry_count: i32,
     pub created_at: Option<String>,
     pub error_message: Option<String>,
+    /// Cached title of the item the operation is about, when the catalog knows
+    /// it. Resolved here rather than by a per-row frontend fetch — the queue
+    /// list is otherwise a wall of opaque ids.
+    ///
+    /// TRACES: UR-025 | DR-132
+    pub item_name: Option<String>,
 }
 
 /// Queue a mutation for sync to server
@@ -74,20 +82,20 @@ pub async fn sync_get_pending(
         Arc::new(database.service())
     };
 
-    let sql = if let Some(l) = limit {
-        format!(
-            "SELECT id, user_id, operation, item_id, payload, status, retry_count, created_at, error_message
-             FROM sync_queue
-             WHERE user_id = ? AND status IN ('pending', 'failed')
-             ORDER BY created_at ASC
-             LIMIT {}",
-            l
-        )
-    } else {
-        "SELECT id, user_id, operation, item_id, payload, status, retry_count, created_at, error_message
-         FROM sync_queue
-         WHERE user_id = ? AND status IN ('pending', 'failed')
-         ORDER BY created_at ASC".to_string()
+    // The `items` join names the queued item where the catalog has it; a row for
+    // an item that was never cached still lists, with a null name.
+    // `abandoned` rows (DR-131 gave up on them) are excluded here for the same
+    // reason they are excluded from the count — they are no longer waiting.
+    const SELECT: &str = "SELECT q.id, q.user_id, q.operation, q.item_id, q.payload, q.status,
+                                 COALESCE(q.retry_count, 0), q.created_at, q.error_message, i.name
+                          FROM sync_queue q
+                          LEFT JOIN items i ON i.id = q.item_id
+                          WHERE q.user_id = ? AND q.status IN ('pending', 'failed')
+                          ORDER BY q.created_at ASC, q.id ASC";
+
+    let sql = match limit {
+        Some(l) => format!("{} LIMIT {}", SELECT, l),
+        None => SELECT.to_string(),
     };
 
     let query = Query::with_params(sql, vec![QueryParam::String(user_id)]);
@@ -104,6 +112,7 @@ pub async fn sync_get_pending(
                 retry_count: row.get(6)?,
                 created_at: row.get(7)?,
                 error_message: row.get(8)?,
+                item_name: row.get(9)?,
             })
         })
         .await
@@ -256,6 +265,7 @@ mod tests {
             retry_count: 0,
             created_at: Some("2024-02-14T08:00:00Z".to_string()),
             error_message: None,
+            item_name: None,
         };
 
         // Should serialize successfully
@@ -280,6 +290,7 @@ mod tests {
             retry_count: 3,
             created_at: Some("2024-02-14T07:00:00Z".to_string()),
             error_message: Some("Connection timeout".to_string()),
+            item_name: None,
         };
 
         let json = serde_json::to_string(&item).unwrap();
@@ -300,6 +311,7 @@ mod tests {
             retry_count: 0,
             created_at: None,
             error_message: None,
+            item_name: None,
         };
 
         let json = serde_json::to_string(&item).unwrap();
@@ -323,6 +335,7 @@ mod tests {
                 retry_count: 0,
                 created_at: None,
                 error_message: None,
+                item_name: None,
             };
 
             let json = serde_json::to_string(&item).unwrap();
@@ -363,6 +376,7 @@ mod tests {
             retry_count: 0,
             created_at: None,
             error_message: None,
+            item_name: None,
         };
 
         // Simulate retries