Migrate all IPC call sites to typed tauri-specta commands.*

Replace the remaining ~155 untyped invoke() calls across stores, services,
components, and routes with the generated commands.* wrappers from
$lib/api/bindings, so every IPC call is compile-time-checked against the
command signatures.

- Register repository_get_subtitle_url and repository_get_video_download_url
  in specta_builder() and the invoke_handler; regenerate bindings.ts.
- Source duplicated wire types (AutoplaySettings, CacheConfig, Session,
  ConnectivityStatus, audio/video settings, etc.) from bindings.
- Fix two bugs surfaced by the typed wrappers:
  - VideoDownloadButton passed an un-awaited Promise as the stream URL.
  - setAutoplaySettings omitted the required userId argument.
- Update unit tests asserting the old invoke(name, args) shape.
- Remove the five param-naming guard tests; the compiler and codegen now
  enforce what they checked.

svelte-check: 0 errors. vitest: green. cargo test --lib: green.

src/lib/components/library/PlaylistDetailView.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount } from "svelte";
   import { goto } from "$app/navigation";
-  import { invoke } from "@tauri-apps/api/core";
+  import { commands } from "$lib/api/bindings";
   import type { MediaItem, PlaylistEntry } from "$lib/api/types";
   import { auth } from "$lib/stores/auth";
   import { toast } from "$lib/stores/toast";
@@ -51,17 +51,14 @@
       const repo = auth.getRepository();
       const repositoryHandle = repo.getHandle();
       const trackIds = entries.map(e => e.id);
-      await invoke("player_play_tracks", {
-        repositoryHandle,
-        request: {
-          trackIds,
-          startIndex: 0,
-          shuffle: false,
-          context: {
-            type: "playlist",
-            playlistId: playlist.id,
-            playlistName: playlist.name,
-          },
+      await commands.playerPlayTracks(repositoryHandle, {
+        trackIds,
+        startIndex: 0,
+        shuffle: false,
+        context: {
+          type: "playlist",
+          playlistId: playlist.id,
+          playlistName: playlist.name,
         },
       });
     } catch (e) {
@@ -76,17 +73,14 @@
       const repo = auth.getRepository();
       const repositoryHandle = repo.getHandle();
       const trackIds = entries.map(e => e.id);
-      await invoke("player_play_tracks", {
-        repositoryHandle,
-        request: {
-          trackIds,
-          startIndex: 0,
-          shuffle: true,
-          context: {
-            type: "playlist",
-            playlistId: playlist.id,
-            playlistName: playlist.name,
-          },
+      await commands.playerPlayTracks(repositoryHandle, {
+        trackIds,
+        startIndex: 0,
+        shuffle: true,
+        context: {
+          type: "playlist",
+          playlistId: playlist.id,
+          playlistName: playlist.name,
         },
       });
     } catch (e) {