feat(library): focused music/TV/movie landing screens + self-draining download queue

Library screens:
- Add dedicated music, TV, and movie landing pages (hero banner +
  horizontal carousels) backed by new music/tv/movies stores.
- Route tvshows libraries to /library/tv; surface rediscover ("haven't
  listened to in a while") albums via a new repository method across
  online/offline/hybrid repos plus the repository_get_rediscover_albums
  command.
- Add an A-Z jump bar for long alphabetically-sorted lists, with grid
  index anchors in LibraryGrid/LibraryListView/TrackList.
- Filter the "Podcasts" folder out of music library queries.

Downloads:
- Add a backend queue pump: enqueue_download / enqueue_video_downloads
  persist the resolved stream URL + target dir on each row (migration
  017), and the pump starts up to max_concurrent and drains the rest
  automatically as slots free, instead of the frontend silently dropping
  items past the concurrency limit. Album/series/season buttons now
  enqueue rather than calling start_download directly.

Other fixes:
- Hybrid search now returns instant cache results and pushes the merged
  cache+server union via a request-id-tagged search-event, so superseded
  queries can't clobber fresher results.
- URL-encode SearchTerm / genres / item types in online repo requests.
- Android: pause on audio-becoming-noisy (headphone/BT disconnect).

src-tauri/src/commands/repository.rs

@@ -7,8 +7,9 @@ use crate::utils::lock::MutexSafe;
 use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
 
-use log::{debug, error, info};
-use tauri::State;
+use log::{debug, error, info, warn};
+use serde::{Deserialize, Serialize};
+use tauri::{AppHandle, Emitter, State};
 use uuid::Uuid;
 
 use crate::jellyfin::HttpClient;
@@ -259,6 +260,21 @@ pub async fn repository_get_resume_movies(
         .map_err(|e| format!("{:?}", e))
 }
 
+/// Get albums the user hasn't listened to recently ("rediscover")
+#[tauri::command]
+#[specta::specta]
+pub async fn repository_get_rediscover_albums(
+    manager: State<'_, RepositoryManagerWrapper>,
+    handle: String,
+    parent_id: Option<String>,
+    limit: Option<usize>,
+) -> Result<Vec<MediaItem>, String> {
+    let repo = manager.0.get(&handle).ok_or("Repository not found")?;
+    repo.as_ref().get_rediscover_albums(parent_id.as_deref(), limit)
+        .await
+        .map_err(|e| format!("{:?}", e))
+}
+
 /// Get genres for a library
 #[tauri::command]
 #[specta::specta]
@@ -273,19 +289,73 @@ pub async fn repository_get_genres(
         .map_err(|e| format!("{:?}", e))
 }
 
+/// Tauri event name carrying the merged (cache + server) search results.
+pub const SEARCH_EVENT_NAME: &str = "search-event";
+
+/// Payload for the deferred, merged search results pushed to the frontend.
+///
+/// `request_id` matches the value the frontend passed to `repository_search`,
+/// letting it discard updates from queries that have since been superseded.
+#[derive(specta::Type, Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SearchUpdateEvent {
+    pub request_id: u32,
+    pub result: SearchResult,
+}
+
 /// Search for items
 #[tauri::command]
 #[specta::specta]
 pub async fn repository_search(
+    app: AppHandle,
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
     query: String,
     options: Option<SearchOptions>,
+    request_id: u32,
 ) -> Result<SearchResult, String> {
     let repo = manager.0.get(&handle).ok_or("Repository not found")?;
-    repo.as_ref().search(&query, options)
+
+    // Phase 1: instant local results from the cache (downloaded content) so the
+    // UI can render immediately while the server is still being queried.
+    let cache_result = repo
+        .search_cache_only(&query, options.clone())
         .await
-        .map_err(|e| format!("{:?}", e))
+        .unwrap_or_else(|e| {
+            debug!("[Search] Cache search miss/timeout: {:?}", e);
+            SearchResult {
+                items: Vec::new(),
+                total_record_count: 0,
+            }
+        });
+
+    // Phase 2: query the live server in the background, merge with the cache,
+    // and push the union to the frontend via a `search-event`. Tagged with
+    // `request_id` so the frontend can discard results from superseded queries.
+    let repo_bg = repo.clone();
+    let cache_for_merge = cache_result.clone();
+    tauri::async_runtime::spawn(async move {
+        match repo_bg.search_server_only(&query, options).await {
+            Ok(server_result) => {
+                let merged =
+                    HybridRepository::merge_search_results(cache_for_merge, server_result);
+                let event = SearchUpdateEvent {
+                    request_id,
+                    result: merged,
+                };
+                if let Err(e) = app.emit(SEARCH_EVENT_NAME, &event) {
+                    error!("[Search] Failed to emit search update: {}", e);
+                }
+            }
+            Err(e) => {
+                // Server failed — the cache results are already on screen, so
+                // just log. (Offline / unreachable server falls here.)
+                warn!("[Search] Server search failed, keeping cache results: {:?}", e);
+            }
+        }
+    });
+
+    Ok(cache_result)
 }
 
 /// Get playback info for an item