fix(host-agent): distinguish connected devices from busy-with-task in console

DeviceManager marks a device "busy" as soon as an Appium/WDA session is
connected, which is unrelated to whether a task is currently executing on
it. The Host Agent's local console displayed this raw status, making
connected-but-idle devices look permanently busy. Cross-reference the
device id against AgentStatusTracker's current_assignment (already
tracked via mark_assignment_started/finished) to show "connected" unless
a task is actually running on that device.

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

@@ -108,6 +108,17 @@ def _login_page(
     return HTMLResponse(_chrome("Login", body, session=None))
 
 
+def _device_display_status(device: Any, *, busy_device_id: str | None) -> str:
+    """Connected-but-idle devices report "busy" at the DeviceManager layer
+    (an active Appium/WDA session is required to reuse it), which is not the
+    same as a task currently running on that device. Only the device actually
+    bound to the current assignment should read as "busy" here.
+    """
+    if device.status == "busy" and device.id != busy_device_id:
+        return "connected"
+    return device.status
+
+
 def _dashboard_body(
     *,
     identity: HostIdentityState | None,
@@ -118,6 +129,7 @@ def _dashboard_body(
     heartbeat = snapshot.get("last_heartbeat")
     assignment = snapshot.get("current_assignment")
     policy = snapshot.get("host_policy")
+    busy_device_id = assignment["device_id"] if assignment else None
     heartbeat_text = (
         f"{'ok' if heartbeat['ok'] else 'failed'} at {heartbeat['at']} "
         f"({heartbeat['device_count']} devices)"
@@ -143,7 +155,8 @@ def _dashboard_body(
     )
     device_rows = "".join(
         f"<tr><td>{escape(device.id)}</td><td>{escape(device.name or '')}</td>"
-        f"<td>{escape(device.driver_type)}</td><td>{escape(device.status)}</td></tr>"
+        f"<td>{escape(device.driver_type)}</td>"
+        f"<td>{escape(_device_display_status(device, busy_device_id=busy_device_id))}</td></tr>"
         for device in devices
     )
     return f"""
@@ -403,12 +416,14 @@ def create_console_app(
         session: SessionState = Depends(require_session),
     ) -> JSONResponse:
         snapshot = status_tracker.snapshot()
+        current_assignment = snapshot.get("current_assignment")
+        busy_device_id = current_assignment["device_id"] if current_assignment else None
         devices = [
             {
                 "id": device.id,
                 "name": device.name,
                 "driver_type": device.driver_type,
-                "status": device.status,
+                "status": _device_display_status(device, busy_device_id=busy_device_id),
             }
             for device in manager.list_devices()
         ]

apps/device-host-agent/tests/test_web_app.py

@@ -1,9 +1,11 @@
 from __future__ import annotations
 
 import re
+from datetime import UTC, datetime
 
 from fastapi.testclient import TestClient
 
+from cloud.internal_api.models import AssignmentModel
 from device.manager import DeviceManager
 from host_agent.config import HostAgentConfig
 from host_agent.history import ConsoleHistoryStore
@@ -53,6 +55,7 @@ def _build_client(tmp_path, *, create_account: bool = True) -> tuple[TestClient,
         "local_account_store": local_account_store,
         "history_store": history_store,
         "session_manager": session_manager,
+        "status_tracker": status_tracker,
     }
     return client, context
 
@@ -119,6 +122,52 @@ def test_login_with_correct_password_sets_cookie_and_dashboard_succeeds(
     assert "control.example" in response.text
 
 
+def test_connected_device_without_running_task_shows_connected_not_busy(
+    tmp_path,
+) -> None:
+    client, context = _build_client(tmp_path)
+    _login(client)
+    context["manager"].register_device(
+        "device-a",
+        lambda: object(),  # type: ignore[arg-type,return-value]
+        status="busy",
+    )
+
+    dashboard_response = client.get("/")
+    api_response = client.get("/api/status")
+
+    assert "connected" in dashboard_response.text
+    assert "<td>busy</td>" not in dashboard_response.text
+    assert api_response.json()["devices"][0]["status"] == "connected"
+
+
+def test_device_running_current_assignment_still_shows_busy(tmp_path) -> None:
+    client, context = _build_client(tmp_path)
+    _login(client)
+    context["manager"].register_device(
+        "device-a",
+        lambda: object(),  # type: ignore[arg-type,return-value]
+        status="busy",
+    )
+    context["status_tracker"].mark_assignment_started(
+        AssignmentModel(
+            task_id="task-a",
+            attempt=1,
+            lease_id="lease-a",
+            lease_expires_at=datetime(2026, 7, 12, tzinfo=UTC),
+            host_id="host-a",
+            device_id="device-a",
+            goal="open settings",
+        )
+    )
+
+    dashboard_response = client.get("/")
+    api_response = client.get("/api/status")
+
+    assert "<td>busy</td>" in dashboard_response.text
+    assert api_response.json()["devices"][0]["status"] == "busy"
+
+
 def test_mutating_post_without_csrf_token_is_rejected_and_makes_no_change(
     tmp_path,
 ) -> None: