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/routes/+layout.svelte

@@ -34,6 +34,9 @@
   import { useScrollRestore } from "$lib/utils/scrollContainer";
   import { startNetworkReporting } from "$lib/services/networkType";
   import { initSafeArea } from "$lib/utils/safeArea";
+  import { createLogger } from "$lib/utils/logger";
+
+  const log = createLogger("Layout");
 
   let { children } = $props();
 
@@ -105,7 +108,7 @@
       const platformName = platform();
       isAndroid.set(platformName === "android");
     } catch (err) {
-      console.error("Platform detection failed:", err);
+      log.error("Platform detection failed:", err);
     }
 
     // Prime the safe-area custom properties from the native WindowInsets bridge
@@ -154,7 +157,7 @@
     const userId = get(auth).user?.id;
     if (userId) {
       downloads.refresh(userId).catch((err) =>
-        console.error("Initial downloads refresh failed:", err)
+        log.error("Initial downloads refresh failed:", err)
       );
     }
 
@@ -168,7 +171,7 @@
     // without spending their retry budget (DR-131).
     if (get(auth).user?.id) {
       commands.syncProcessPending().catch((err) =>
-        console.debug("[Layout] Startup sync drain skipped:", err)
+        log.debug("Startup sync drain skipped:", err)
       );
     }
 
@@ -206,7 +209,7 @@
         if (session?.serverUrl) {
           connectivity.forceCheck().catch((error) => {
             // If check fails, monitoring might not be started yet, so start it
-            console.debug("[Layout] Queue status check failed, starting monitoring:", error);
+            log.debug("Queue status check failed, starting monitoring:", error);
             connectivity.startMonitoring(session.serverUrl, {
               onServerReconnected: () => {
                 // Retry session verification when server becomes reachable
@@ -215,7 +218,7 @@
                 void onCatalogReconnected();
               },
             }).catch((monitorError) => {
-              console.error("[Layout] Failed to start connectivity monitoring:", monitorError);
+              log.error("Failed to start connectivity monitoring:", monitorError);
             });
           });
         }
@@ -242,7 +245,7 @@
         .then((unlisten) => {
           unlistenDrain = unlisten;
         })
-        .catch((err) => console.debug("[Layout] sync-queue-changed listen failed:", err));
+        .catch((err) => log.debug("sync-queue-changed listen failed:", err));
 
       return () => {
         clearInterval(interval);