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

tests/adapter/matrix/test_restart_persistence.py

@@ -6,24 +6,13 @@ from adapter.matrix.bot import build_runtime
 from adapter.matrix.reconciliation import reconcile_startup_state
 from adapter.matrix.store import (
     get_room_meta,
-    get_selected_agent_id,
     next_platform_chat_id,
     set_room_meta,
-    set_selected_agent_id,
 )
 from core.store import SQLiteStore
 from sdk.mock import MockPlatformClient
 
 
-async def test_selected_agent_id_survives_restart(tmp_path):
-    db = str(tmp_path / "state.db")
-    store = SQLiteStore(db)
-    await set_selected_agent_id(store, "@alice:example.org", "agent-2")
-
-    store2 = SQLiteStore(db)
-    assert await get_selected_agent_id(store2, "@alice:example.org") == "agent-2"
-
-
 async def test_room_agent_id_and_platform_chat_id_survive_restart(tmp_path):
     db = str(tmp_path / "state.db")
     store = SQLiteStore(db)
@@ -54,7 +43,6 @@ async def test_platform_chat_seq_survives_restart(tmp_path):
 async def test_routing_state_survives_restart_and_routes_correctly(tmp_path):
     db = str(tmp_path / "state.db")
     store = SQLiteStore(db)
-    await set_selected_agent_id(store, "@bob:example.org", "agent-1")
     await set_room_meta(store, "!convo:example.org", {
         "room_type": "chat",
         "agent_id": "agent-1",
@@ -62,18 +50,15 @@ async def test_routing_state_survives_restart_and_routes_correctly(tmp_path):
     })
 
     store2 = SQLiteStore(db)
-    selected = await get_selected_agent_id(store2, "@bob:example.org")
     meta = await get_room_meta(store2, "!convo:example.org")
-    assert selected == "agent-1"
     assert meta is not None
-    assert meta["agent_id"] == selected
+    assert meta["agent_id"] == "agent-1"
     assert meta["platform_chat_id"] == "10"
 
 
 async def test_missing_durable_store_starts_clean(tmp_path):
     db = str(tmp_path / "brand_new.db")
     store = SQLiteStore(db)
-    assert await get_selected_agent_id(store, "@nobody:example.org") is None
     assert await get_room_meta(store, "!nonexistent:example.org") is None