feat(scheduling): multi-node service placement + remote lifecycle (#54)

* feat(scheduling): multi-node service placement + remote container lifecycle

services.node_id pins a service to a node agent: explicit id, "auto"
(least-loaded online node), or "local"/empty for the local Docker host.

- DeploymentEngine gains a NodeRunner seam; ReconcileService routes
  pinned services to the agent's command queue (create_container with
  image/env/command/ports/volumes/labels/resource limits), tracked in
  container_instances with deterministic per-replica ids.
- Stop/start/restart/delete fan out to the pinned node — no more leaked
  remote containers on service delete.
- Agent create_container is idempotent (rm -f first) and honors restart
  policy, labels, memory/cpus, published+ephemeral ports, volumes, env.
- GET /nodes/options exposes id/name/status to authed users; full agent
  management stays admin-only.
- CLI services create/update --node, MCP node_id docs, OpenAPI
  node_id/node_name + /nodes/options, service-detail Placement section.

Ceilings: remote nodes run registry-pulled images only — git builds,
Traefik domains, and remote sleep detection stay local until
build-on-node and per-node ingress land.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* feat(scheduling): node cordon/drain + schedulable gate

- node_agents.schedulable column; "auto" placement and explicit pins skip
  cordoned nodes; already-pinned services keep running (reconcile is
  unaffected — cordon is not eviction).
- POST /agents/:id/cordon|uncordon|drain (admin). Drain cordons, removes
  every service container via the agent queue, and clears the services'
  pins so they redeploy on the local host. Requires the node online —
  an offline node can't acknowledge removals.
- CLI nodes cordon|uncordon|drain (drain confirm-gated), MCP
  containr_nodes_cordon|uncordon|drain, OpenAPI paths + schedulable
  field, node-detail page cordon badge + drain/cordon controls.
- Fix: re-registering an agent no longer resets auto_prune.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* feat(scheduling): remote registry pulls + post-run health check

- Dispatch payload carries the project owner's registry credentials for
  the image host; the agent docker-logins for the pull and logs out
  after, so private images deploy to remote nodes.
- Completed command payloads get their registry password scrubbed —
  secrets don't linger in agent_commands rows.
- Agent verifies the container is still running ~1.5s after docker run;
  crash-loops now fail the deployment with the container's last log
  lines instead of reporting "running" optimistically.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/src/features/service/pages/ServiceDetailPage.tsx

@@ -48,6 +48,7 @@ import {
   cloneService,
   moveService,
   listProjects,
+  listNodeOptions,
 } from '@/lib/api-client';
 import { getDemoProjectById, getDemoServiceById, getDemoCronJobsByService } from '@/lib/demo-data';
 import { useDemoMode } from '@/lib/demo-mode';
@@ -466,6 +467,7 @@ export function ServiceDetailPage() {
     onSuccess: () => {
       setNetworkForm(null);
       setSleepDraft(null);
+      setNodeDraft(null);
       invalidateService();
     },
   });
@@ -485,6 +487,13 @@ export function ServiceDetailPage() {
   const [domainChecks, setDomainChecks] = useState<Record<string, DomainCheckResult> | null>(null);
   const [accessForm, setAccessForm] = useState<{ maintenance: boolean; basicAuth: string } | null>(null);
   const [sleepDraft, setSleepDraft] = useState<{ id: string; enabled: boolean; minutes: string } | null>(null);
+  const [nodeDraft, setNodeDraft] = useState<string | null>(null);
+  const nodesQuery = useQuery({
+    queryKey: ['node-options'],
+    queryFn: listNodeOptions,
+    enabled: !isDemoMode,
+    staleTime: 30_000,
+  });
   const [buildForm, setBuildForm] = useState<{
     builder: string; cpuReserve: string; memoryReserve: string; staticCmd: string; staticDir: string;
   } | null>(null);
@@ -2384,6 +2393,58 @@ export function ServiceDetailPage() {
               </div>
             )}
 
+            {!isDemoMode && (nodesQuery.data?.length ?? 0) > 0 && (
+              <div className="mt-6 pt-6 border-t border-[var(--border-subtle)]">
+                <div className="mb-3">
+                  <h3 className="text-sm font-medium text-[var(--text-primary)]">Placement</h3>
+                  <p className="text-xs text-[var(--text-tertiary)] mt-0.5">
+                    Which node runs this service's containers. Remote nodes pull the image
+                    from its registry — git builds and domains stay on the local host.
+                  </p>
+                </div>
+                <div className="flex items-center gap-3 text-xs">
+                  <select
+                    value={nodeDraft ?? (service.nodeId || 'local')}
+                    onChange={(e) => setNodeDraft(e.target.value)}
+                    className="px-2 py-1.5 rounded-[var(--radius-md)] bg-[var(--surface-muted)] border border-[var(--border-subtle)] text-sm text-[var(--text-primary)]"
+                  >
+                    <option value="local">This server (local Docker)</option>
+                    <option value="auto">Auto — least-loaded online node</option>
+                    {(nodesQuery.data ?? []).map((n) => (
+                      <option key={n.id} value={n.id}>
+                        {n.name}{n.status !== 'online' ? ' (offline)' : ''}
+                      </option>
+                    ))}
+                  </select>
+                  {nodeDraft !== null && (
+                    <>
+                      <button
+                        type="button"
+                        disabled={updateServiceMutation.isPending}
+                        onClick={() => updateServiceMutation.mutate({ node_id: nodeDraft })}
+                        className="px-3 py-1.5 rounded-[var(--radius-md)] bg-[var(--accent-primary)] text-[var(--accent-on)] text-xs font-medium disabled:opacity-50"
+                      >
+                        Save
+                      </button>
+                      <button
+                        type="button"
+                        onClick={() => setNodeDraft(null)}
+                        className="text-[var(--text-tertiary)] hover:text-[var(--text-primary)]"
+                      >
+                        Cancel
+                      </button>
+                    </>
+                  )}
+                  {service.nodeName && nodeDraft === null && (
+                    <span className="text-[var(--text-tertiary)]">running on {service.nodeName}</span>
+                  )}
+                </div>
+                {updateServiceMutation.isError && (
+                  <p className="mt-2 text-xs text-[var(--error)]">{(updateServiceMutation.error as Error).message}</p>
+                )}
+              </div>
+            )}
+
             {!isDemoMode && (
               <div className="mt-6 pt-6 border-t border-[var(--border-subtle)]">
                 <div className="flex items-center justify-between mb-4">