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/music.ts

@@ -7,6 +7,9 @@ import { auth } from "./auth";
 import { excludePodcasts } from "$lib/utils/podcastFilter";
 import { selectDiverseGenres, sampleAcross } from "$lib/utils/genreDiversity";
 import { buildHeroMix } from "$lib/utils/heroMix";
+import { createLogger } from "$lib/utils/logger";
+
+const log = createLogger("MusicStore");
 
 /** A single "by genre" row: the genre name plus the albums in it. */
 export interface GenreRow {
@@ -124,7 +127,7 @@ function createMusicStore() {
     } catch (error) {
       const message = error instanceof Error ? error.message : "Failed to load music sections";
       update(s => ({ ...s, isLoading: false, error: message }));
-      console.error("Failed to load music sections:", error);
+      log.error("Failed to load music sections:", error);
     }
   }
 
@@ -143,7 +146,7 @@ function createMusicStore() {
       // HACK: drop the "Podcasts" folder that lives in the music library.
       return { id: genre.id, name: genre.name, items: excludePodcasts(result.items) };
     } catch (e) {
-      console.warn(`Failed to load genre row "${genre.name}":`, e);
+      log.warn(`Failed to load genre row "${genre.name}":`, e);
       return { id: genre.id, name: genre.name, items: [] };
     }
   }
@@ -205,7 +208,7 @@ function createMusicStore() {
 
       update(s => ({ ...s, genreRows }));
     } catch (e) {
-      console.warn("Failed to load music genre rows:", e);
+      log.warn("Failed to load music genre rows:", e);
     }
   }