refactor(logging): route frontend console calls through the logger

TRACES: | DR-204

484 ungated `console.*` calls across 63 non-test frontend files shipped to
end users with no way to turn them off. Mechanical substitution, no control
flow, error handling or message semantics changed:

  console.log / console.debug -> log.debug
  console.info                -> log.info
  console.warn                -> log.warn
  console.error               -> log.error

Hand-written `"[Scope] …"` prefixes are dropped where the logger's scope
now carries them; scope names that already existed are preserved verbatim
(`[Auth]`, `[VideoPlayer]`, `[PiP]`, …) and inferred from the filename
where a file had none. `src/routes/player/[id]/+page.svelte` keeps its
`NextEpisode` and `AutoPlay` sub-scopes as separate loggers rather than
flattening them into the page scope.

`grep -rn 'console\.' src/` now matches nothing outside the tests and the
facade itself.

src/lib/services/favorites.ts

@@ -6,6 +6,9 @@ import { commands } from "$lib/api/bindings";
 import { auth } from "$lib/stores/auth";
 import { isConnected } from "$lib/stores/connectivity";
 import { setFavorite } from "$lib/stores/favorites";
+import { createLogger } from "$lib/utils/logger";
+
+const log = createLogger("Favorites");
 
 /**
  * Toggle the favorite status of an item.
@@ -59,7 +62,7 @@ export async function toggleFavorite(
       // 3. Mark as synced
       await commands.storageMarkSynced(userId, itemId);
     } catch (error) {
-      console.error("Failed to sync favorite to server:", error);
+      log.error("Failed to sync favorite to server:", error);
       // Favorite is stored locally and will be synced later
       // via sync queue (when implemented)
     }