feat(deploy): platform handoff — agent routing, persistence, docs cleanup

Agent routing:
- Remove !agent command and manual agent selection flow
- Registry auto-assigns agent from user_agents mapping (fallback: agents[0])
- provision_workspace_chat and !new both write agent_id to room_meta
- Reconciliation backfills agent_id from registry on cold start
- Fix duplicate agent_id block in auth.py

Deployment stability:
- Add bot-state named volume to persist lambda_matrix.db and matrix_store
- Fix docker-compose.prod.yml duplicate environment: key (was silently losing all Matrix credentials)
- Fix MATRIX_AGENT_REGISTRY_PATH to use absolute container path /app/config/...
- Add bot-state volume declaration to docker-compose.fullstack.yml

Docs and config:
- Rewrite README.md for platform handoff (deploy table, working commands only)
- Rewrite docs/matrix-prototype.md (remove stale commands and mock descriptions)
- Remove !save/!load/!context/!agent from help text and welcome message
- Add !clear, !list, !remove, !yes/!no to help text
- Clean up .env.example (remove Telegram token, internal vars, real URLs)
- Update config/matrix-agents.example.yaml with user_agents section and comments
- Add explanatory comment to Dockerfile for --ignore-requires-python
- Remove silent uv sync fallbacks in Dockerfile

docker-compose.fullstack.yml

@@ -30,7 +30,7 @@ services:
       sh -lc "
         mkdir -p /workspace &&
         chown -R agent:agent /workspace &&
-        exec /app/.venv/bin/uvicorn src.main:app --host 0.0.0.0 --port 8000
+        exec /app/.venv/bin/uvicorn src.main:app --host 0.0.0.0 --port 8000 --no-access-log
       "
     ports:
       - "8000:8000"
@@ -38,12 +38,14 @@ services:
       test:
         - CMD-SHELL
         - python -c "import urllib.request; urllib.request.urlopen('http://127.0.0.1:8000/openapi.json', timeout=2).read()"
-      interval: 10s
+      interval: 60s
       timeout: 5s
       retries: 5
-      start_period: 10s
+      start_period: 15s
     restart: unless-stopped
 
 volumes:
   agents:
     name: ${SURFACES_SHARED_VOLUME:-surfaces-agents}
+  bot-state:
+    name: ${SURFACES_BOT_STATE_VOLUME:-surfaces-bot-state}