Add archive message pagination, configurable WS replay buffer ...

Backend:
- Add archive_threshold to Session model and getSession response
- Add next_before_seq to archive endpoint for cursor pagination
- Make WS replay buffer size configurable via WS_REPLAY_BUFFER_SIZE

Webclient:
- Add getArchivedMessages API function
- Add archive pagination state and loadArchivedMessages to chat store
- MessageList: auto-load older messages on scroll-to-top with scroll
  position preservation and loading spinner

Docs: update config.md with new env vars

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

Audit and fix docs/ for accuracy against current codebase ...

Package A (API + WebSocket + Sessions):
- api.md: add missing endpoints (health/embed, auth/status, agents/prompts,
  agents/mcp_servers, sessions/content, 7 admin endpoints). Fix response
  schemas, auth requirements, query params. Update path formats.
- websocket.md: fix planning_status.phase type (int 1|2|3), add metadata
  to tool_call, message_index to stream_end, context_tokens/max_context_tokens
  to context_compressed.
- sessions.md: fix context_compression_threshold default (0.80→0.70),
  add list_page method, add metadata to Message flags.

Package B (Config + Profiles + Tools + Agent + Memory):
- config.md: remove stale ANTHROPIC_API_KEY description, add 12 missing
  env vars (embedding, web search, terminal_user_allowed_commands,
  context_providers_dir, gnauth fields, output_reserve_tokens).
  Fix OPENAI_BASE_URL type.
- profiles.md: fix max_iterations default (20→10), add top_k/top_p/num_thread,
  is_admin_only, context_providers, mcp_servers, subagent_think_enabled.
  Clarify subagent_tools fallback and step_validation_enabled.
- tools.md: replace 3 separate memory tools with unified `memory`, add
  `mcp_status`.
- agent.md: fix run_ephemeral return type (str→tuple), clarify DB reads.
- memory.md: fix search_facts/get_all_facts param order, fix MemoryStore
  init description.

236 tests passing.

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

Document multi-user auth system ...

- New docs/auth.md — comprehensive auth guide: OAuth flow, roles/permissions,
  webhooks, env vars, setup instructions, API reference, WebSocket auth,
  testing with mocked auth
- Update docs/config.md — add gnexus-auth OAuth env vars table
- Update docs/api.md — add /auth/*, /admin/*, /webhooks/gnexus-auth endpoints
- Update docs/index.md — add auth.md to file map
- Update docs/sessions.md — document user_id column and list_all filtering
- Update docs/memory.md — document user_id scoping in facts and summaries

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

Clarify share file publishing boundaries

Update deployment docs — PostgreSQL-only, new .env vars, pg_trgm notes ...

- README.md: remove SQLite, add PostgreSQL setup (Ubuntu/Arch/Docker),
  add pg_trgm notes, update .env example
- docs/config.md: remove DB_PATH, add OLLAMA_REQUEST_TIMEOUT / OPENAI_MODEL /
  OPENAI_BASE_URL, update example .env
- .env.example: rewrite with all current variables and comments

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

WelcomeScreen polish, root-path fix, docs update ...

- Move mobile sidebar button to top-left corner (no header bar backdrop)
- Show WelcomeScreen on / with no hash instead of auto-loading first session
- Docs: document Ollama multi-server fallback, model priority lists, OLLAMA_BACKENDS_FILE

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Make server I/O non-blocking; update docs ...

- Wrap all heavy filesystem ops in asyncio.to_thread: filesystem tool
  (read/write/append/list/find/info/move/delete/query/smart_edit),
  image_view (read_bytes), share_file (shutil.copy2), write_tool
  (write_text, _register_user_tool), session_files (shutil.rmtree,
  iterdir), sessions upload endpoint (sync open/write → to_thread)
- Make delete_session_dir async; update its caller in sessions.py
- docs/config.md: fix wrong defaults (threshold 0.70, keep_recent 8),
  remove phantom SESSION_FILES_TTL_HOURS, add LLM timeouts, DATABASE_URL,
  PUBLIC_URL, Gmail, CONTEXT_SUMMARY_MAX_TOKENS sections
- docs/profiles.md: add missing tool_developer profile to table
- android-client: add WebView remote debugging; remove unused toolbar menu
- Remove stale helper scripts and test files

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Use gemma4 cloud model by default

Support Ollama Cloud API key

Add backend documentation ...

10 markdown files covering all backend subsystems: architecture,
agent loop, tool system, sessions, WebSocket protocol, profiles,
memory, config, and API reference. Structured for AI readability
with a single entry point (docs/index.md) and cross-references.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>