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/common/CachedImage.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { invoke } from "@tauri-apps/api/core";
+  import { commands } from "$lib/api/bindings";
   import { auth } from "$lib/stores/auth";
   import { get } from "svelte/store";
 
@@ -47,15 +47,12 @@
       const repositoryHandle = repository.getHandle();
 
       // Call Rust to get image as base64 data URL
-      const dataUrl = await invoke<string>("image_get_url", {
-        repositoryHandle,
-        request: {
-          itemId,
-          imageType,
-          maxWidth,
-          maxHeight,
-          tag,
-        },
+      const dataUrl = await commands.imageGetUrl(repositoryHandle, {
+        itemId,
+        imageType,
+        maxWidth,
+        maxHeight,
+        tag,
       });
 
       // Use data URL directly