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/stores/lmsSync.ts

@@ -16,6 +16,9 @@ import { writable, get } from "svelte/store";
 import { commands } from "$lib/api/bindings";
 import type { Session } from "$lib/api/types";
 import type { LmsSyncGroup } from "$lib/api/bindings";
+import { createLogger } from "$lib/utils/logger";
+
+const log = createLogger("LmsSync");
 
 const LMS_DEVICE_PREFIX = "lms-";
 
@@ -51,7 +54,7 @@ function createLmsSyncStore() {
       update((s) => ({ ...s, groups, error: null }));
     } catch (error) {
       // The plugin may not be installed; treat as "no groups" rather than fatal.
-      console.warn("[LmsSync] Failed to load sync groups:", error);
+      log.warn("Failed to load sync groups:", error);
       update((s) => ({ ...s, groups: [] }));
     }
   }