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/vector/qdrant_client.py

@@ -89,6 +89,8 @@ async def get_qdrant_client() -> AsyncQdrantClient:
             if isinstance(vectors, dict):
                 actual_dimension = vectors["dense"].size
             else:
+                # Type narrowing: vectors must be VectorParams if not dict
+                assert isinstance(vectors, VectorParams)
                 actual_dimension = vectors.size
 
             # Validate dimension matches