Add debug logging to trace MCP tool registration / resolution ...

Logs added to:
- _on_mcp_server_connected: shows how many tools are registered per server
- build_tool_list: lists missing tool names and counts
- _resolve_tool: dumps tool_map keys when a lookup fails

This is diagnostic — will be removed once the root cause is found.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Add MCP health check loop, auto-reconnect, and system toast notifications ...

Backend:
- McpManager: keep all configured servers in the pool even if connect()
  fails at startup; health-check loop (30s) tries to reconnect dead servers
  and verifies live ones with list_tools()
- McpManager: set_on_server_connected callback re-registers tools when a
  dead server comes back online
- McpClient: add mark_disconnected() for silent drop detection
- McpStatusTool: skip list_tools() for disconnected servers
- Orchestrator: broadcast mcp_status_update to all WebSocket sessions
- New event type McpStatusUpdate with server_name, status, tool_count

Webclient:
- useWebSocket: handle mcp_status_update → toast.success/toast.error

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Fix stop button responsiveness and shutdown CancelledError ...

Agent loop (_execute_tools_with_sink):
- Poll stop_event every 1s while draining the event sink via asyncio.wait_for
- When stopped, cancel the tool task, yield a synthetic ToolEvent failure,
  append a cancellation message to session, yield StreamStopped, and return
- Pass stop_event into _execute_tools_with_sink call site

Subagent runner:
- Check stop_event at the start of each tool in turn_tool_calls loop
- Returns early with ("", False) when stopped mid-batch

McpManager.disconnect_all():
- Disconnect clients sequentially instead of asyncio.gather
- Handle asyncio.CancelledError per-client to avoid shutdown traceback

AppContainer.shutdown():
- Catch BaseException instead of Exception for MCP and DB cleanup

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Fix UnboundLocalError: create mcp_manager before build_default_registries ...

The previous commit passed mcp_manager to build_default_registries but
left the instantiation after the call, causing UnboundLocalError at
runtime. Move McpManager() creation before the registry build and
remove the now-obsolete post-hoc _mcp_manager patching loop.

392 passed, 1 skipped

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Eliminate cross-registry patching in registry.py via proper creation order ...

- Reorder build_default_registries so profiles and cp_registry are created
  BEFORE tools that need them
- All tools now receive full dependencies at construction time:
  ListToolsTool(profile_registry=profiles, mcp_manager=mcp_manager)
  SpawnAgentTool(backend_registry=backends, ...)
  ReloadToolsTool(cp_registry=cp_registry, mcp_manager=mcp_manager)
- Remove all post-creation patch lines (_profile_registry, _backend_registry, _cp_registry)
- Add mcp_manager parameter to build_default_registries
- Update create_container to pass mcp_manager

392 passed, 1 skipped

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Extract single shared Database pool, eliminate 4 duplicated pool creations ...

- Create navi/db.py::Database managing one asyncpg pool
- KvStore, PgSessionStore, MemoryStore, RecallScheduler now accept pool in constructor
- AppContainer holds Database, shutdown closes one pool instead of 4
- create_container creates one pool and passes it to all stores
- All tests updated to set _initialized=True on fakes to skip DDL

392 passed, 1 skipped

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Extract WebSocket business logic into AgentSessionOrchestrator ...

- Create navi/core/orchestrator.py with AgentSessionOrchestrator and SessionRun
- Orchestrator owns _runs, _busy_sessions, Agent creation, run_agent(), run_recall()
- Transport-agnostic: accepts notify callback from WebSocket handler
- WebSocket handler (websocket.py) now only does serialization/deserialization
- _fire_recall delegates to orchestrator.run_recall() instead of inline logic
- recall_scheduler_loop now accepts orchestrator parameter
- AppContainer gains .orchestrator field, created in create_container()
- deps.py: add get_orchestrator()
- Update integration tests for scheduler_loop and websocket unit tests

All 392 tests pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Fix PgSessionStore import in container.py ...

`PgSessionStore` lives in `navi.core.pg_session_store`, not `navi.core.session`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Replace global lazy singletons with explicit AppContainer + lifespan ...

- Create navi/core/container.py with AppContainer dataclass and create_container()
- Rewrite navi/api/deps.py: remove module-level singletons, add _container global
  fallback + set_container(), use _resolve_container() for all getters
- Replace @app.on_event with @asynccontextmanager lifespan in main.py
- Update routes to use Depends(get_scheduler) instead of calling get_scheduler()
- Fix FastAPI body parsing bug: remove dataclass parameters from Depends getters
  (FastAPI was treating AppContainer sub-dependencies as Body params, forcing
  embed=True on all endpoint body params and causing 422 errors)
- Update websocket.py to use _resolve_container() instead of get_registries()
- Update integration test fixtures to build AppContainer and call set_container()
- Remove obsolete tests/unit/test_startup.py (tests removed _on_startup)
- Fix test_scheduler_loop.py fixture (get_registries no longer exists)

All 387 tests pass (excluding websocket hang tests).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>