Fix 1 (bootstrap.py): wrap store.flush() in asyncio.to_thread() inside the
periodic _flush_loop() to avoid blocking the async event loop every 60s.
Synchronous signatures of _start/_stop_model_usage_persistence() and the
one-time seed/shutdown flushes are left unchanged per review scope.
Fix 2 (test_stream_chat_usage_capture.py): add the two-line stream_options
assertion to test_qwen_vl_stream_chat_returns_usage_from_trailing_chunk,
matching the identical check already present in the DeepSeek and Qwen tests.
Fix 3 (design doc): note the single-worker assumption in A3's write strategy
section — multi-worker deployments get last-writer-wins per-row semantics.
Tests: 69 passed, 0 failed (python -m pytest backend/tests -q)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
feat(agent): update import for agent session service
feat(openai): add context truncation check in OpenAI answer generator
docs(README): update frontend environment file conventions
fix(vite): default local frontend development to local backend
Move session-related responsibilities into a new application-layer AgentSessionService (and AgentSessionFeedbackResult dataclass), provide a bootstrap factory (get_agent_session_service), and update agent API routes to call the service instead of accessing ConversationStore directly. Routes now translate ValueError into 404 responses and use service methods for get/list/history/delete/feedback. Also update package exports and docs/READMEs to declare the backend architecture authority, enforce api -> application -> domain ports -> infrastructure boundaries, and call out legacy services/workflows as migration-only. These changes centralize session logic in the application layer and tighten architecture guidance for future backend work.
