Backend:
- Stop session auth bypass: require auth for owned sessions, reject anonymous with 401
- upload_file: stream chunks directly to disk instead of buffering in RAM
- MCP config: validate name against path traversal regex
- auth deps: cleanup stale refresh locks periodically
- auth routes: expire mobile auth states after 10 min to prevent unbounded growth
- compressor: meta-summarize existing summaries before compression; preserve assistant content when tool_calls present; rewrite hard_truncate to keep whole turns
- orchestrator: configurable WS replay buffer size; async cleanup/remove_websocket/clear_busy; fix run_recall ContextVar order to avoid deadlock on _build_agent failure; await cleanup in finally
- agent: persist image_msg in session.messages; remove archived messages from session after archive; remove duplicate StreamStopped yield on tool stop
- websocket: try/except around create_task with cleanup on failure; await remove_websocket

Frontend:
- App.vue: hashchange listener lifecycle in onMounted/onUnmounted
- MessageList.vue: passive scroll, flash timeout cleanup, archive scroll snapshot
- InputBar.vue: 300 ms debounce on draft save to localStorage
- SessionList.vue: remove :key from DynamicScroller to avoid remount jitter

Tests: 422 passed, 1 skipped

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

Replace scattered _runs + _busy_sessions + _session_sockets with a
single _sessions: dict[str, SessionState] on the orchestrator.

- SessionState dataclass holds run, busy_event, and websockets
- _session_sockets module-level global removed from websocket.py;
  socket tracking moved into orchestrator (add/remove_websocket)
- Event bus subscriber _on_recall_update moved into orchestrator
- Per-session asyncio.Lock added to protect concurrent-run guard
- _cleanup() auto-removes empty SessionState entries

Tests updated to reference _sessions instead of legacy _runs.

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

- 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>

Tests for reconnect/replay, concurrent-run guard, event buffering,
and session_sync behavior after both normal and recall runs.

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