fix(device-pool): scope primary key by host and thread through capability_tags

- pooled_devices primary key changed from device_id alone to
  (host_id, device_id), so two hosts reporting the same local
  device_id no longer crash sync_host_devices() with an uncaught
  sqlite3.IntegrityError.
- Device gained a capability_tags field so DevicePool.sync_host_devices()
  can actually populate PooledDevice.capability_tags from a real host
  sync instead of always falling back to an empty list.

openspec: device-pool capability, archived change cloud-runtime

tests/test_device_pool.py

@@ -23,8 +23,19 @@ def _config(**overrides) -> CloudConfig:
     return CloudConfig(**base)
 
 
-def _device(device_id: str, *, status: str = "idle", driver_type: str = "wda") -> Device:
-    return Device(id=device_id, status=status, driver_type=driver_type)  # type: ignore[arg-type]
+def _device(
+    device_id: str,
+    *,
+    status: str = "idle",
+    driver_type: str = "wda",
+    capability_tags: list[str] | None = None,
+) -> Device:
+    return Device(
+        id=device_id,
+        status=status,  # type: ignore[arg-type]
+        driver_type=driver_type,
+        capability_tags=list(capability_tags or []),
+    )
 
 
 def test_new_host_sync_creates_registration_and_devices(tmp_path) -> None:
@@ -140,3 +151,37 @@ def test_two_hosts_aggregate_into_one_listing(tmp_path) -> None:
         "b-dev-1": "host-b",
         "b-dev-2": "host-b",
     }
+
+
+def test_two_hosts_syncing_same_local_device_id_do_not_crash(tmp_path) -> None:
+    """Two hosts legitimately reporting the same local device_id are distinct
+    devices in the pool; syncing both must succeed and yield two entries."""
+    pool = DevicePool(CloudStore(tmp_path / "cloud.sqlite3"), _config())
+    pool.sync_host_devices("host-a", [_device("dev-1", status="idle")], address="a")
+    pool.sync_host_devices("host-b", [_device("dev-1", status="busy")], address="b")
+
+    devices = pool.list_devices()
+    assert len(devices) == 2
+    by_host = {d.host_id: d for d in devices}
+    assert set(by_host) == {"host-a", "host-b"}
+    assert by_host["host-a"].device_id == "dev-1"
+    assert by_host["host-b"].device_id == "dev-1"
+    assert by_host["host-a"].status == "idle"
+    assert by_host["host-b"].status == "busy"
+
+
+def test_capability_tags_flow_from_device_to_pooled_device(tmp_path) -> None:
+    pool = DevicePool(CloudStore(tmp_path / "cloud.sqlite3"), _config())
+    pool.sync_host_devices(
+        "host-a",
+        [_device("dev-1", capability_tags=["ios", "physical"])],
+        address="a",
+    )
+
+    devices = pool.list_devices()
+    assert len(devices) == 1
+    assert devices[0].capability_tags == ["ios", "physical"]
+
+    fetched = pool.get_device("dev-1")
+    assert fetched is not None
+    assert fetched.capability_tags == ["ios", "physical"]