feat(api): GET /deckies/lifecycle + master startup sweep

GET /deckies/lifecycle?ids=<uuid>&ids=<uuid> returns the matching
DeckyLifecycle rows so the wizard can poll instead of holding an HTTP
request open across compose work. require_viewer gating -- read-only.

Startup sweep: on master boot, any pending/running row with
started_at older than 1h flips to failed with
error='master restarted during operation'. Pre-v1 substitute for a
durable task queue: if the master crashes mid-deploy, the wizard sees
FAILED on refresh and the operator retries. Idempotent + cheap; runs
unconditionally including in contract-test mode.

tests/api/fleet/test_lifecycle_endpoint.py

@@ -0,0 +1,85 @@
+"""GET /deckies/lifecycle?ids=… — poll endpoint for the wizard."""
+from __future__ import annotations
+
+import httpx
+import pytest
+
+from decnet.web.dependencies import repo
+
+
+@pytest.mark.anyio
+async def test_get_lifecycle_unauthenticated_returns_401(client: httpx.AsyncClient):
+    resp = await client.get("/api/v1/deckies/lifecycle", params={"ids": "x"})
+    assert resp.status_code == 401
+
+
+@pytest.mark.anyio
+async def test_get_lifecycle_missing_ids_returns_validation_error(
+    client: httpx.AsyncClient, auth_token: str,
+):
+    """No ?ids= → validation rejection (Starlette short-circuits with 400
+    for the body-parse path; either 400 or 422 is acceptable contract)."""
+    resp = await client.get(
+        "/api/v1/deckies/lifecycle",
+        headers={"Authorization": f"Bearer {auth_token}"},
+    )
+    assert resp.status_code in (400, 422)
+
+
+@pytest.mark.anyio
+async def test_get_lifecycle_returns_matching_rows(
+    client: httpx.AsyncClient, auth_token: str,
+):
+    a = await repo.create_lifecycle({"decky_name": "d1", "operation": "deploy"})
+    b = await repo.create_lifecycle({"decky_name": "d2", "operation": "mutate"})
+    await repo.update_lifecycle(a, {"status": "running"})
+
+    resp = await client.get(
+        "/api/v1/deckies/lifecycle",
+        params=[("ids", a), ("ids", b)],
+        headers={"Authorization": f"Bearer {auth_token}"},
+    )
+    assert resp.status_code == 200, resp.text
+    rows = resp.json()["rows"]
+    assert len(rows) == 2
+    by_id = {r["id"]: r for r in rows}
+    assert by_id[a]["status"] == "running"
+    assert by_id[a]["operation"] == "deploy"
+    assert by_id[b]["status"] == "pending"
+    assert by_id[b]["operation"] == "mutate"
+
+
+@pytest.mark.anyio
+async def test_get_lifecycle_unknown_id_silently_omitted(
+    client: httpx.AsyncClient, auth_token: str,
+):
+    a = await repo.create_lifecycle({"decky_name": "d1", "operation": "deploy"})
+    resp = await client.get(
+        "/api/v1/deckies/lifecycle",
+        params=[("ids", a), ("ids", "no-such-id")],
+        headers={"Authorization": f"Bearer {auth_token}"},
+    )
+    assert resp.status_code == 200
+    rows = resp.json()["rows"]
+    assert len(rows) == 1
+    assert rows[0]["id"] == a
+
+
+@pytest.mark.anyio
+async def test_startup_sweep_marks_stale_rows_failed():
+    """The sweep stamps reason='master restarted during operation' on
+    any non-terminal row older than the cutoff."""
+    from datetime import datetime, timedelta, timezone
+    lid = await repo.create_lifecycle({"decky_name": "stale", "operation": "deploy"})
+    # Backdate started_at into the past so the sweep picks it up.
+    await repo.update_lifecycle(
+        lid, {"started_at": datetime.now(timezone.utc) - timedelta(hours=2)},
+    )
+    swept = await repo.sweep_stale_lifecycle(
+        datetime.now(timezone.utc) - timedelta(hours=1),
+        reason="master restarted during operation",
+    )
+    assert swept >= 1
+    rows = await repo.get_lifecycle_by_ids([lid])
+    assert rows[0]["status"] == "failed"
+    assert rows[0]["error"] == "master restarted during operation"