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/components/FavoriteButton.svelte

@@ -4,6 +4,9 @@
   import { haptics } from "$lib/utils/haptics";
   import { toast } from "$lib/stores/toast";
   import { favoriteOverrides } from "$lib/stores/favorites";
+  import { createLogger } from "$lib/utils/logger";
+
+  const log = createLogger("FavoriteButton");
 
   interface Props {
     itemId: string;
@@ -78,7 +81,7 @@
         isAnimating = false;
       }, 600);
     } catch (error) {
-      console.error("Failed to toggle favorite:", error);
+      log.error("Failed to toggle favorite:", error);
       toast.show("Failed to update favorites", "error");
       isAnimating = false;
     } finally {