fix: resolve type checking warnings for CI

- Add type casts for Starlette app state access
- Add assertions for cipher, card, board, stack after initialization
- Add None checks for XML element text attributes
- Handle __package__ being None in tracing setup
- Fix TokenBrokerService initialization to use storage credentials

Resolves 42 type warnings from ty-check, enabling CI linting to pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

nextcloud_mcp_server/auth/storage.py

@@ -216,6 +216,8 @@ class RefreshTokenStorage:
         if not self._initialized:
             await self.initialize()
 
+        # Type narrowing: cipher is set after initialize()
+        assert self.cipher is not None
         encrypted_token = self.cipher.encrypt(refresh_token.encode())
         now = int(time.time())
         scopes_json = json.dumps(scopes) if scopes else None
@@ -361,6 +363,9 @@ class RefreshTokenStorage:
         if not self._initialized:
             await self.initialize()
 
+        # Type narrowing: cipher is set after initialize()
+        assert self.cipher is not None
+
         start_time = time.time()
         try:
             async with aiosqlite.connect(self.db_path) as db:
@@ -445,6 +450,9 @@ class RefreshTokenStorage:
         if not self._initialized:
             await self.initialize()
 
+        # Type narrowing: cipher is set after initialize()
+        assert self.cipher is not None
+
         async with aiosqlite.connect(self.db_path) as db:
             async with db.execute(
                 """
@@ -616,6 +624,9 @@ class RefreshTokenStorage:
         if not self._initialized:
             await self.initialize()
 
+        # Type narrowing: cipher is set after initialize()
+        assert self.cipher is not None
+
         # Encrypt sensitive data
         encrypted_secret = self.cipher.encrypt(client_secret.encode())
         encrypted_reg_token = (
@@ -686,6 +697,9 @@ class RefreshTokenStorage:
         if not self._initialized:
             await self.initialize()
 
+        # Type narrowing: cipher is set after initialize()
+        assert self.cipher is not None
+
         async with aiosqlite.connect(self.db_path) as db:
             async with db.execute(
                 """