refactor local directory agent to two-phase LLM-with-tools architecture

Replace the single-pass FE-driven agent_run/agent_data flow with a
BE-orchestrated two-phase execution using LangChain tool-calling:
- Phase 1 (Triage): explores directory via new filesystem tools, matches
  files to existing projects using PROJECT_TOOLS
- Phase 2 (Processing): reads files and performs CRUD per project group
  with clean LLM context windows

Key changes:
- Add filesystem_agent.py with list_directory, read_file_content,
  get_file_metadata tools using execute_on_client()
- Move setup journey from REST to WebSocket (journey_start/message frames)
- Add batch_runs_per_day billing limit and enforce in /trigger
- Remove deprecated agent_data/agent_complete frame handlers and queues

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

app/api/routes/device_ws.py

@@ -14,11 +14,11 @@ Protocol:
   4. Session enters message dispatch loop + heartbeat.
 
 Incoming frame dispatch:
-  - ``tool_result``    → resolves a pending tool-call Future.
-  - ``agent_data``     → enqueued in the per-run agent data queue.
-  - ``agent_complete`` → sends None sentinel to close the queue stream.
-  - ``pong``           → heartbeat acknowledgement (updates last-seen).
-  - unknown types      → logged, ignored.
+  - ``tool_result``      → resolves a pending tool-call Future.
+  - ``journey_start``    → starts a guided setup journey session.
+  - ``journey_message``  → continues a journey conversation.
+  - ``pong``             → heartbeat acknowledgement (updates last-seen).
+  - unknown types        → logged, ignored.
 
 Outgoing heartbeat: ``{ "type": "ping" }`` every 30 s.
 
@@ -39,6 +39,7 @@ from fastapi import APIRouter, WebSocket, WebSocketDisconnect
 from jose import JWTError, jwt
 from sqlalchemy import update
 
+from app.api.routes.agent_setup import handle_journey_message, handle_journey_start
 from app.config.settings import settings
 from app.core.agent_runner import trigger_pending_runs
 from app.core.deep_agent import run_floating_stream, run_home_stream
@@ -147,37 +148,6 @@ async def _message_loop(websocket: WebSocket, user_id: str) -> None:
                     "device_ws: tool_result missing id from user=%s", user_id
                 )
 
-        elif frame_type == WsFrameType.agent_data:
-            run_id = frame.get("run_id")
-            if run_id:
-                try:
-                    queue = device_manager.get_agent_data_queue(user_id, run_id)
-                    await queue.put(frame)
-                except RuntimeError:
-                    logger.warning(
-                        "device_ws: agent_data for unknown run user=%s run=%s",
-                        user_id,
-                        run_id,
-                    )
-            else:
-                logger.warning(
-                    "device_ws: agent_data missing run_id from user=%s", user_id
-                )
-
-        elif frame_type == WsFrameType.agent_complete:
-            run_id = frame.get("run_id")
-            if run_id:
-                try:
-                    queue = device_manager.get_agent_data_queue(user_id, run_id)
-                    # Sentinel: signals the agent data stream is finished.
-                    await queue.put(None)
-                except RuntimeError:
-                    pass
-            else:
-                logger.warning(
-                    "device_ws: agent_complete missing run_id from user=%s", user_id
-                )
-
         elif frame_type == WsFrameType.home_request:
             asyncio.create_task(
                 _handle_home_request(websocket, user_id, frame)
@@ -188,6 +158,16 @@ async def _message_loop(websocket: WebSocket, user_id: str) -> None:
                 _handle_floating_request(websocket, user_id, frame)
             )
 
+        elif frame_type == WsFrameType.journey_start:
+            asyncio.create_task(
+                _handle_journey_start(websocket, user_id, frame)
+            )
+
+        elif frame_type == WsFrameType.journey_message:
+            asyncio.create_task(
+                _handle_journey_message(websocket, user_id, frame)
+            )
+
         elif frame_type == "pong":
             # Heartbeat ack — nothing to do, connection is alive.
             pass
@@ -345,6 +325,63 @@ async def _handle_floating_request(
     )
 
 
+# ── v4 Journey Handlers ─────────────────────────────────────────────
+
+
+async def _handle_journey_start(
+    websocket: WebSocket,
+    user_id: str,
+    frame: dict,
+) -> None:
+    """Handle a journey_start frame — explores directory and sends first question."""
+    executor = await _make_ws_executor(websocket, user_id)
+    set_client_executor(executor)
+    try:
+        reply = await handle_journey_start(user_id, frame)
+        await websocket.send_text(json.dumps(reply))
+    except Exception as exc:
+        logger.error(
+            "device_ws: journey_start failed user=%s: %s", user_id, exc
+        )
+        await websocket.send_text(json.dumps({
+            "type": "journey_reply",
+            "session_id": frame.get("session_id", ""),
+            "message": f"Failed to start journey: {exc}",
+            "done": True,
+            "prompt_template": None,
+        }))
+    finally:
+        clear_client_executor()
+
+
+async def _handle_journey_message(
+    websocket: WebSocket,
+    user_id: str,
+    frame: dict,
+) -> None:
+    """Handle a journey_message frame — continues the journey conversation."""
+    executor = await _make_ws_executor(websocket, user_id)
+    set_client_executor(executor)
+    try:
+        reply = await handle_journey_message(user_id, frame)
+        await websocket.send_text(json.dumps(reply))
+    except Exception as exc:
+        session_id = frame.get("session_id", "")
+        logger.error(
+            "device_ws: journey_message failed user=%s session=%s: %s",
+            user_id, session_id, exc,
+        )
+        await websocket.send_text(json.dumps({
+            "type": "journey_reply",
+            "session_id": session_id,
+            "message": f"Journey error: {exc}",
+            "done": True,
+            "prompt_template": None,
+        }))
+    finally:
+        clear_client_executor()
+
+
 # ── Heartbeat ─────────────────────────────────────────────────────────
 
 async def _heartbeat_loop(websocket: WebSocket) -> None:
@@ -378,6 +415,3 @@ async def _mark_runs_disconnected(user_id: str) -> None:
             user_id,
             exc,
         )
-
-
-