feat(host-agent): wire MCP server into create_application

apps/device-host-agent/host_agent/app.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import asyncio
+import logging
 from contextlib import suppress
 from dataclasses import dataclass
 
@@ -21,6 +22,8 @@ from host_agent.identity import HostIdentityStore
 from host_agent.instance_lock import InstanceLock
 from host_agent.lease import ActiveAssignmentRunner
 from host_agent.local_account import LocalAccountStore
+from host_agent.mcp_lock import McpBusyTracker
+from host_agent.mcp_token import McpTokenStore
 from host_agent.policy_cache import HostPolicyCacheStore
 from host_agent.processor import AssignmentProcessingResult, AssignmentProcessor
 from host_agent.retention import prune_task_history
@@ -28,6 +31,7 @@ from host_agent.skill_sync import HostAgentSkillSync
 from host_agent.status import AgentStatusTracker
 from host_agent.web.app import create_console_app
 from host_agent.web.auth import SessionManager
+from host_agent.web.mcp import build_mcp_server
 from storage.artifact_store import ArtifactStore
 from storage.device_config import DeviceConfigStore
 from storage.task_metadata import TaskMetadataStore
@@ -201,13 +205,28 @@ def create_application(
             db_path=resolved_config.task_progress_db_path
         )
         timeline = Timeline(ArtifactStore(root=resolved_config.task_artifact_dir))
+        mcp_token_path = resolved_config.identity_path.parent / "host_mcp_token.json"
+        mcp_token_existed = mcp_token_path.exists()
+        mcp_token_store = McpTokenStore(mcp_token_path)
+        mcp_token_store.load_or_create()
+        if not mcp_token_existed:
+            logging.getLogger(__name__).info(
+                "MCP token generated at %s", mcp_token_path
+            )
+        mcp_busy_tracker = McpBusyTracker(ttl_seconds=60.0)
         executor = AssignmentExecutor(
             create_execution_factories(
                 resolved_manager,
                 metadata_store=metadata_store,
                 timeline=timeline,
                 host_agent_config=resolved_config,
-            )
+            ),
+            mcp_busy_tracker=mcp_busy_tracker,
+        )
+        mcp_server = build_mcp_server(
+            manager=resolved_manager,
+            mcp_busy_tracker=mcp_busy_tracker,
+            status_tracker=status_tracker,
         )
         console_app = create_console_app(
             config=resolved_config,
@@ -225,6 +244,9 @@ def create_application(
             metadata_store=metadata_store,
             timeline=timeline,
             executor=executor,
+            mcp_server=mcp_server,
+            mcp_token_store=mcp_token_store,
+            mcp_busy_tracker=mcp_busy_tracker,
         )
         console_server = _EmbeddedConsoleServer(
             uvicorn.Config(
@@ -240,6 +262,7 @@ def create_application(
             client,
             resolved_config,
             status_tracker=status_tracker,
+            mcp_busy_tracker=mcp_busy_tracker,
             on_sync=lambda device_count: history_store.record_heartbeat(
                 device_count=device_count
             ),