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

.env.example

@@ -1,25 +1,24 @@
-# Telegram
-TELEGRAM_BOT_TOKEN=your_bot_token_here
-
-# Matrix
-MATRIX_HOMESERVER=https://matrix.org
-MATRIX_USER_ID=@bot:matrix.org
+# Matrix bot credentials
+MATRIX_HOMESERVER=https://matrix.example.org
+MATRIX_USER_ID=@lambda-bot:example.org
+# Use ONE of: MATRIX_PASSWORD or MATRIX_ACCESS_TOKEN
 MATRIX_PASSWORD=your_password_here
+# MATRIX_ACCESS_TOKEN=your_access_token_here
+
+# Backend: "real" connects to platform-agent via AgentApi; "mock" uses local stub (testing only)
 MATRIX_PLATFORM_BACKEND=real
-MATRIX_AGENT_REGISTRY_PATH=config/matrix-agents.yaml
 
-# Shared /agents contract for Phase 05 deployment
+# Path to agent registry inside the container (mounted via ./config:/app/config:ro)
+MATRIX_AGENT_REGISTRY_PATH=/app/config/matrix-agents.yaml
+
+# HTTP URL of the platform-agent endpoint
+# Production: external agent managed by the platform
+# Fullstack E2E: overridden to http://platform-agent:8000 by docker-compose.fullstack.yml
+AGENT_BASE_URL=http://your-agent-host:8000
+
+# Shared volume path inside the bot container (default: /agents)
 SURFACES_WORKSPACE_DIR=/agents
+
+# Docker volume names (created automatically on first run)
 SURFACES_SHARED_VOLUME=surfaces-agents
-
-# Production handoff: point the bot at the externally managed agent endpoint.
-AGENT_BASE_URL=https://lambda.coredump.ru/agent_0/
-
-# Internal full-stack compose defaults
-AGENT_ID=matrix-dev
-COMPOSIO_API_KEY=
-
-# platform-agent provider
-PROVIDER_MODEL=openai/gpt-4o-mini
-PROVIDER_URL=https://openrouter.ai/api/v1
-PROVIDER_API_KEY=sk-or-...
+SURFACES_BOT_STATE_VOLUME=surfaces-bot-state