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/library/PlaylistDetailView.svelte

@@ -10,6 +10,9 @@
   import FavoriteButton from "$lib/components/FavoriteButton.svelte";
   import { favoriteOverrides } from "$lib/stores/favorites";
   import { formatDuration } from "$lib/utils/duration";
+  import { createLogger } from "$lib/utils/logger";
+
+  const log = createLogger("PlaylistDetail");
 
   interface Props {
     playlist: MediaItem;
@@ -40,7 +43,7 @@
       const repo = auth.getRepository();
       entries = await repo.getPlaylistItems(playlist.id);
     } catch (e) {
-      console.error("[PlaylistDetail] Failed to load items:", e);
+      log.error("Failed to load items:", e);
       toast.error("Failed to load playlist items");
     } finally {
       loading = false;
@@ -62,7 +65,7 @@
         },
       });
     } catch (e) {
-      console.error("[PlaylistDetail] Failed to play all:", e);
+      log.error("Failed to play all:", e);
       toast.error("Failed to play playlist");
     }
   }
@@ -82,7 +85,7 @@
         },
       });
     } catch (e) {
-      console.error("[PlaylistDetail] Failed to shuffle play:", e);
+      log.error("Failed to shuffle play:", e);
       toast.error("Failed to shuffle playlist");
     }
   }
@@ -100,7 +103,7 @@
       playlist.name = trimmed;
       toast.success("Playlist renamed");
     } catch (e) {
-      console.error("[PlaylistDetail] Failed to rename:", e);
+      log.error("Failed to rename:", e);
       toast.error("Failed to rename playlist");
       editName = playlist.name;
     } finally {
@@ -115,7 +118,7 @@
       toast.success("Playlist deleted");
       goto("/library");
     } catch (e) {
-      console.error("[PlaylistDetail] Failed to delete:", e);
+      log.error("Failed to delete:", e);
       toast.error("Failed to delete playlist");
     } finally {
       showDeleteConfirm = false;
@@ -129,7 +132,7 @@
       entries = entries.filter(e => e.playlistItemId !== entry.playlistItemId);
       toast.success("Track removed");
     } catch (e) {
-      console.error("[PlaylistDetail] Failed to remove track:", e);
+      log.error("Failed to remove track:", e);
       toast.error("Failed to remove track");
     }
   }