feat(swarm): persist DeckyConfig snapshot per shard + enrich list API

Dispatch now writes the full serialised DeckyConfig into
DeckyShard.decky_config (plus decky_ip as a cheap extract), so the
master can render the same rich per-decky card the local-fleet view
uses — hostname, distro, archetype, service_config, mutate_interval,
last_mutated — without round-tripping to the worker on every page
render. DeckyShardView gains the corresponding fields; the repository
flattens the snapshot at read time. Pre-migration rows keep working
(fields fall through as None/defaults).

Columns are additive + nullable so SQLModel.metadata.create_all handles
the change on both SQLite and MySQL. Backfill happens organically on
the next dispatch or (in a follow-up) agent heartbeat.

decnet/web/router/swarm/api_deploy_swarm.py

@@ -89,6 +89,8 @@ async def dispatch_decnet_config(
                         "decky_name": d.name,
                         "host_uuid": host_uuid,
                         "services": json.dumps(d.services),
+                        "decky_config": d.model_dump_json(),
+                        "decky_ip": d.ip,
                         "state": "running" if not dry_run else "pending",
                         "last_error": None,
                         "updated_at": datetime.now(timezone.utc),
@@ -118,6 +120,8 @@ async def dispatch_decnet_config(
                         "decky_name": d.name,
                         "host_uuid": host_uuid,
                         "services": json.dumps(d.services),
+                        "decky_config": d.model_dump_json(),
+                        "decky_ip": d.ip,
                         "state": "running" if is_up else "failed",
                         "last_error": None if is_up else str(exc)[:512],
                         "updated_at": datetime.now(timezone.utc),