fix: resolve auth callback failure from IndexedDB cache issues (refs #188)

Add allKeys() to IndexedDBStorage to eliminate Auth0 CacheKeyManifest
fallback, revert set()/remove() to non-blocking persist, add auth error
display on callback route, remove leaky force-auth-check interceptor,
and migrate debug console calls to centralized logger.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/core/utils/indexeddb-storage.ts

@@ -3,6 +3,8 @@
  * @ai-context Replaces localStorage with IndexedDB for mobile browser compatibility
  */
 
+import logger from '../../utils/logger';
+
 interface StorageAdapter {
   getItem(key: string): string | null;
   setItem(key: string, value: string): void;
@@ -36,9 +38,9 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
       this.db = await this.openDatabase();
       await this.loadCacheFromDB();
       this.isReady = true;
-      console.log('[IndexedDB] Storage initialized successfully');
+      logger.debug('IndexedDB storage initialized successfully');
     } catch (error) {
-      console.error('[IndexedDB] Initialization failed, using memory only:', error);
+      logger.error('IndexedDB initialization failed, using memory only', { error: String(error) });
       this.isReady = false;
     }
   }
@@ -48,7 +50,7 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
       const request = indexedDB.open(this.dbName, this.dbVersion);
 
       request.onerror = () => {
-        console.error(`IndexedDB open failed: ${request.error?.message}`);
+        logger.error(`IndexedDB open failed: ${request.error?.message}`);
         resolve(null as any); // Fallback to memory-only mode
       };
 
@@ -84,13 +86,13 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
           }
           cursor.continue();
         } else {
-          console.log(`[IndexedDB] Loaded ${this.memoryCache.size} items into cache`);
+          logger.debug(`IndexedDB loaded ${this.memoryCache.size} items into cache`);
           resolve();
         }
       };
 
       request.onerror = () => {
-        console.warn('[IndexedDB] Failed to load cache from DB:', request.error);
+        logger.warn('IndexedDB failed to load cache from DB', { error: String(request.error) });
         resolve();
       };
     });
@@ -107,14 +109,14 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
         const request = store.delete(key);
         request.onsuccess = () => resolve();
         request.onerror = () => {
-          console.warn(`[IndexedDB] Failed to delete ${key}:`, request.error);
+          logger.warn(`IndexedDB failed to delete ${key}`, { error: String(request.error) });
           resolve();
         };
       } else {
         const request = store.put(value, key);
         request.onsuccess = () => resolve();
         request.onerror = () => {
-          console.warn(`[IndexedDB] Failed to persist ${key}:`, request.error);
+          logger.warn(`IndexedDB failed to persist ${key}`, { error: String(request.error) });
           resolve();
         };
       }
@@ -132,7 +134,7 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
     // Async persist to IndexedDB (non-blocking)
     if (this.isReady) {
       this.persistToDB(key, value).catch(error => {
-        console.warn(`[IndexedDB] Background persist failed for ${key}:`, error);
+        logger.warn(`IndexedDB background persist failed for ${key}`, { error: String(error) });
       });
     }
   }
@@ -143,7 +145,7 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
     // Async remove from IndexedDB (non-blocking)
     if (this.isReady) {
       this.persistToDB(key, null).catch(error => {
-        console.warn(`[IndexedDB] Background removal failed for ${key}:`, error);
+        logger.warn(`IndexedDB background removal failed for ${key}`, { error: String(error) });
       });
     }
   }
@@ -193,6 +195,11 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
   }
 
   // Auth0 Cache interface implementation
+  // allKeys() eliminates Auth0 SDK's CacheKeyManifest fallback (auth0-spa-js line 2319)
+  allKeys(): string[] {
+    return Array.from(this.memoryCache.keys());
+  }
+
   async get(key: string): Promise<any> {
     await this.initPromise;
     const value = this.getItem(key);
@@ -203,13 +210,19 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
     await this.initPromise;
     const stringValue = JSON.stringify(value);
     this.memoryCache.set(key, stringValue);
-    await this.persistToDB(key, stringValue);
+    // Fire-and-forget: persist to IndexedDB for page reload survival
+    this.persistToDB(key, stringValue).catch(error => {
+      logger.warn(`IndexedDB background persist failed for ${key}`, { error: String(error) });
+    });
   }
 
   async remove(key: string): Promise<void> {
     await this.initPromise;
     this.memoryCache.delete(key);
-    await this.persistToDB(key, null);
+    // Fire-and-forget: remove from IndexedDB
+    this.persistToDB(key, null).catch(error => {
+      logger.warn(`IndexedDB background removal failed for ${key}`, { error: String(error) });
+    });
   }
 
   // Additional methods for enhanced functionality