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.

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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/backend/internal/deployment/runtime.go

@@ -55,6 +55,8 @@ type RuntimeSpec struct {
 	Maintenance    bool          // redirect traffic to MaintenanceURL
 	MaintenanceURL string        // absolute URL; empty = serve empty response
 	BasicAuthUsers string        // htpasswd-format user:hash pairs, comma-separated
+	// NodeID pins the service to a node agent; "" runs on the local host.
+	NodeID string
 }
 
 // RuntimeContainer describes one live replica.
@@ -151,8 +153,15 @@ func (de *DeploymentEngine) ListServiceContainers(ctx context.Context, serviceID
 
 // ReconcileService brings live containers in line with the spec. When the
 // spec hash changed (image/env/ports/etc.) all replicas are recreated;
-// otherwise only the replica delta is applied.
+// otherwise only the replica delta is applied. A pinned NodeID routes the
+// whole reconcile to that agent's command queue instead of local Docker.
 func (de *DeploymentEngine) ReconcileService(ctx context.Context, spec RuntimeSpec) (*RuntimeState, error) {
+	if spec.NodeID != "" {
+		if de.nodeRunner == nil {
+			return nil, fmt.Errorf("service is pinned to node %s but remote dispatch is unavailable", spec.NodeID)
+		}
+		return de.nodeRunner.ReconcileOnNode(ctx, spec)
+	}
 	if spec.Replicas < 1 {
 		spec.Replicas = 1
 	}
@@ -498,6 +507,25 @@ func (de *DeploymentEngine) RemoveServiceContainers(ctx context.Context, service
 	return nil
 }
 
+// ControlServiceOnNode fans a lifecycle action out to the service's replicas
+// on a remote node agent. Callers resolve the pin; nil runner means the
+// platform was booted without node support.
+func (de *DeploymentEngine) ControlServiceOnNode(ctx context.Context, serviceID, nodeID, action string) error {
+	if de.nodeRunner == nil {
+		return fmt.Errorf("remote node control is not configured")
+	}
+	return de.nodeRunner.ControlService(ctx, serviceID, nodeID, action)
+}
+
+// RemoveServiceContainersOnNode tears down the service's replicas on a remote
+// node agent.
+func (de *DeploymentEngine) RemoveServiceContainersOnNode(ctx context.Context, serviceID, nodeID string) error {
+	if de.nodeRunner == nil {
+		return fmt.Errorf("remote node control is not configured")
+	}
+	return de.nodeRunner.RemoveService(ctx, serviceID, nodeID)
+}
+
 // RemoveProjectContainers deletes every managed container in a project.
 func (de *DeploymentEngine) RemoveProjectContainers(ctx context.Context, projectID string) error {
 	containers, err := de.dockerClient.ListContainersFiltered(ctx, filters.NewArgs(