feat(swarm): add decnet swarm deckies to list deployed shards by host

`swarm list` only shows enrolled workers — there was no way to see which
deckies are running and where. Adds GET /swarm/deckies on the controller
(joins DeckyShard with SwarmHost for name/address/status) plus the CLI
wrapper with --host / --state filters and --json.

tests/swarm/test_cli_swarm.py

@@ -152,6 +152,65 @@ def test_swarm_check_json_output(http_stub) -> None:
     assert '"decky01"' in result.output
 
 
+# ------------------------------------------------------------- swarm deckies
+
+
+def test_swarm_deckies_empty(http_stub) -> None:
+    http_stub.script[("GET", "/swarm/deckies")] = _FakeResp([])
+    result = runner.invoke(app, ["swarm", "deckies"])
+    assert result.exit_code == 0, result.output
+    assert "No deckies" in result.output
+
+
+def test_swarm_deckies_renders_table(http_stub) -> None:
+    http_stub.script[("GET", "/swarm/deckies")] = _FakeResp([
+        {"decky_name": "decky-01", "host_uuid": "u-1", "host_name": "w1",
+         "host_address": "10.0.0.1", "host_status": "active",
+         "services": ["ssh"], "state": "running", "last_error": None,
+         "compose_hash": None, "updated_at": "2026-04-18T00:00:00Z"},
+        {"decky_name": "decky-02", "host_uuid": "u-2", "host_name": "w2",
+         "host_address": "10.0.0.2", "host_status": "active",
+         "services": ["smb", "ssh"], "state": "failed", "last_error": "boom",
+         "compose_hash": None, "updated_at": "2026-04-18T00:00:00Z"},
+    ])
+    result = runner.invoke(app, ["swarm", "deckies"])
+    assert result.exit_code == 0, result.output
+    assert "decky-01" in result.output
+    assert "decky-02" in result.output
+    assert "w1" in result.output and "w2" in result.output
+    assert "smb,ssh" in result.output
+
+
+def test_swarm_deckies_json_output(http_stub) -> None:
+    http_stub.script[("GET", "/swarm/deckies")] = _FakeResp([
+        {"decky_name": "decky-01", "host_uuid": "u-1", "host_name": "w1",
+         "host_address": "10.0.0.1", "host_status": "active",
+         "services": ["ssh"], "state": "running", "last_error": None,
+         "compose_hash": None, "updated_at": "2026-04-18T00:00:00Z"},
+    ])
+    result = runner.invoke(app, ["swarm", "deckies", "--json"])
+    assert result.exit_code == 0
+    assert '"decky_name"' in result.output
+    assert '"decky-01"' in result.output
+
+
+def test_swarm_deckies_filter_by_host_name_looks_up_uuid(http_stub) -> None:
+    http_stub.script[("GET", "/swarm/hosts")] = _FakeResp([
+        {"uuid": "u-x", "name": "w1"},
+    ])
+    http_stub.script[("GET", "/swarm/deckies?host_uuid=u-x")] = _FakeResp([])
+    result = runner.invoke(app, ["swarm", "deckies", "--host", "w1"])
+    assert result.exit_code == 0
+    assert http_stub[-1][1].endswith("/swarm/deckies?host_uuid=u-x")
+
+
+def test_swarm_deckies_filter_by_state(http_stub) -> None:
+    http_stub.script[("GET", "/swarm/deckies?state=failed")] = _FakeResp([])
+    result = runner.invoke(app, ["swarm", "deckies", "--state", "failed"])
+    assert result.exit_code == 0
+    assert http_stub[-1][1].endswith("/swarm/deckies?state=failed")
+
+
 # ------------------------------------------------------------- swarm decommission
 
 

tests/swarm/test_swarm_api.py

@@ -287,6 +287,57 @@ def test_check_marks_hosts_active(client: TestClient, stub_agent) -> None:
     assert one["last_heartbeat"] is not None
 
 
+# ---------------------------------------------------------------- /deckies
+
+
+def test_list_deckies_empty(client: TestClient) -> None:
+    resp = client.get("/swarm/deckies")
+    assert resp.status_code == 200
+    assert resp.json() == []
+
+
+def test_list_deckies_joins_host_identity(client: TestClient, repo) -> None:
+    import asyncio
+
+    h1 = client.post(
+        "/swarm/enroll",
+        json={"name": "deck-host-1", "address": "10.0.0.11", "agent_port": 8765},
+    ).json()
+    h2 = client.post(
+        "/swarm/enroll",
+        json={"name": "deck-host-2", "address": "10.0.0.12", "agent_port": 8765},
+    ).json()
+
+    async def _seed() -> None:
+        await repo.upsert_decky_shard({
+            "decky_name": "decky-01", "host_uuid": h1["host_uuid"],
+            "services": ["ssh"], "state": "running",
+        })
+        await repo.upsert_decky_shard({
+            "decky_name": "decky-02", "host_uuid": h2["host_uuid"],
+            "services": ["smb", "ssh"], "state": "failed", "last_error": "boom",
+        })
+
+    asyncio.get_event_loop().run_until_complete(_seed())
+
+    rows = client.get("/swarm/deckies").json()
+    assert len(rows) == 2
+    by_name = {r["decky_name"]: r for r in rows}
+    assert by_name["decky-01"]["host_name"] == "deck-host-1"
+    assert by_name["decky-01"]["host_address"] == "10.0.0.11"
+    assert by_name["decky-01"]["state"] == "running"
+    assert by_name["decky-02"]["services"] == ["smb", "ssh"]
+    assert by_name["decky-02"]["last_error"] == "boom"
+
+    # host_uuid filter
+    only = client.get(f"/swarm/deckies?host_uuid={h1['host_uuid']}").json()
+    assert [r["decky_name"] for r in only] == ["decky-01"]
+
+    # state filter
+    failed = client.get("/swarm/deckies?state=failed").json()
+    assert [r["decky_name"] for r in failed] == ["decky-02"]
+
+
 # ---------------------------------------------------------------- /health (root)