feat(swarm): DeckyConfig.host_uuid + fix agent log/status field refs

- decnet.models.DeckyConfig grows an optional 'host_uuid' (the SwarmHost
  that runs this decky). Defaults to None so legacy unihost state files
  deserialize unchanged.
- decnet.agent.executor: replace non-existent config.name references
  with config.mode / config.interface in logs and status payload.
- tests/swarm/test_state_schema.py covers legacy-dict roundtrip, field
  default, and swarm-mode assignments.

decnet/agent/executor.py

@@ -21,7 +21,10 @@ log = get_logger("agent.executor")
 async def deploy(config: DecnetConfig, dry_run: bool = False, no_cache: bool = False) -> None:
     """Run the blocking deployer off-loop. The deployer itself calls
     save_state() internally once the compose file is materialised."""
-    log.info("agent.deploy name=%s deckies=%d", config.name, len(config.deckies))
+    log.info(
+        "agent.deploy mode=%s deckies=%d interface=%s",
+        config.mode, len(config.deckies), config.interface,
+    )
     await asyncio.to_thread(_deployer.deploy, config, dry_run, no_cache, False)
 
 
@@ -39,7 +42,7 @@ async def status() -> dict[str, Any]:
     config, _compose_path = state
     return {
         "deployed": True,
-        "name": getattr(config, "name", None),
+        "mode": config.mode,
         "compose_path": str(_compose_path),
         "deckies": [d.model_dump() for d in config.deckies],
     }

decnet/models.py

@@ -99,6 +99,9 @@ class DeckyConfig(BaseModel):
     mutate_interval: int | None = None  # automatic rotation interval in minutes
     last_mutated: float = 0.0     # timestamp of last mutation
     last_login_attempt: float = 0.0 # timestamp of most recent interaction
+    # SWARM: the SwarmHost.uuid that runs this decky. None in unihost mode
+    # so existing state files deserialize unchanged.
+    host_uuid: str | None = None
 
     @field_validator("services")
     @classmethod

tests/swarm/test_state_schema.py

@@ -0,0 +1,60 @@
+"""Backward-compatibility tests for the SWARM state-schema extension.
+
+DeckyConfig gained an optional ``host_uuid`` field in swarm mode.  Existing
+state files (unihost) must continue to deserialize without change.
+"""
+from __future__ import annotations
+
+from decnet.models import DeckyConfig, DecnetConfig
+
+
+def _minimal_decky(name: str = "decky-01") -> dict:
+    return {
+        "name": name,
+        "ip": "192.168.1.10",
+        "services": ["ssh"],
+        "distro": "debian",
+        "base_image": "debian:bookworm-slim",
+        "hostname": "decky01",
+    }
+
+
+def test_decky_config_host_uuid_defaults_to_none() -> None:
+    """A decky built from a pre-swarm state blob lands with host_uuid=None."""
+    d = DeckyConfig(**_minimal_decky())
+    assert d.host_uuid is None
+
+
+def test_decky_config_accepts_host_uuid() -> None:
+    d = DeckyConfig(**_minimal_decky(), host_uuid="host-uuid-abc")
+    assert d.host_uuid == "host-uuid-abc"
+
+
+def test_decnet_config_mode_swarm_with_host_assignments() -> None:
+    """Full swarm-mode config: every decky carries a host_uuid."""
+    config = DecnetConfig(
+        mode="swarm",
+        interface="eth0",
+        subnet="192.168.1.0/24",
+        gateway="192.168.1.1",
+        deckies=[
+            DeckyConfig(**_minimal_decky("decky-01"), host_uuid="host-A"),
+            DeckyConfig(**_minimal_decky("decky-02"), host_uuid="host-B"),
+        ],
+    )
+    assert config.mode == "swarm"
+    assert {d.host_uuid for d in config.deckies} == {"host-A", "host-B"}
+
+
+def test_legacy_unihost_state_still_parses() -> None:
+    """A dict matching the pre-swarm schema deserializes unchanged."""
+    legacy_blob = {
+        "mode": "unihost",
+        "interface": "eth0",
+        "subnet": "192.168.1.0/24",
+        "gateway": "192.168.1.1",
+        "deckies": [_minimal_decky()],
+    }
+    config = DecnetConfig.model_validate(legacy_blob)
+    assert config.mode == "unihost"
+    assert config.deckies[0].host_uuid is None