fix(auto-update): proxy update execution to remote nodes via Distributed API (#419)

* fix(auto-update): proxy update execution to remote nodes via Distributed API

Remote auto-update policies previously failed because the scheduler tried
to access the Docker daemon directly on remote nodes. Now the scheduler
detects remote nodes and proxies the update execution via HTTP to the
remote Sencho instance's new /api/auto-update/execute endpoint, which
runs image checks and compose updates locally on the remote machine.

* test(auto-update): add getNode mock to NodeRegistry in scheduler tests

The executeUpdate method now calls NodeRegistry.getNode() to detect
remote nodes. The test mock for NodeRegistry was missing this method,
causing the two executeUpdate tests to fail.

backend/src/services/SchedulerService.ts

@@ -369,12 +369,18 @@ export class SchedulerService {
             throw new Error('Auto-update requires target_id (stack name or "*") and node_id');
         }
 
-        // Resolve target stacks: "*" means all stacks on the node
+        // For remote nodes, proxy the entire execution to the remote Sencho instance
+        const node = NodeRegistry.getInstance().getNode(task.node_id);
+        if (node?.type === 'remote') {
+            return this.executeUpdateRemote(task.node_id, task.target_id);
+        }
+
+        // Local node: execute directly
         let stackNames: string[];
         if (task.target_id === '*') {
             stackNames = await FileSystemService.getInstance(task.node_id).getStacks();
             if (stackNames.length === 0) {
-                return 'No stacks found on node — skipped.';
+                return 'No stacks found on node; skipped.';
             }
         } else {
             stackNames = [task.target_id];
@@ -400,6 +406,36 @@ export class SchedulerService {
         return results.join('\n');
     }
 
+    /**
+     * Proxy auto-update execution to a remote Sencho instance.
+     * The remote node runs the image checks and compose update locally.
+     */
+    private async executeUpdateRemote(nodeId: number, target: string): Promise<string> {
+        const proxyTarget = NodeRegistry.getInstance().getProxyTarget(nodeId);
+        if (!proxyTarget) {
+            throw new Error('Remote node is not configured or missing API credentials');
+        }
+
+        const baseUrl = proxyTarget.apiUrl.replace(/\/$/, '');
+        const response = await fetch(`${baseUrl}/api/auto-update/execute`, {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+                'Authorization': `Bearer ${proxyTarget.apiToken}`,
+            },
+            body: JSON.stringify({ target }),
+            signal: AbortSignal.timeout(300_000), // 5 minute timeout for long updates
+        });
+
+        if (!response.ok) {
+            const body = await response.json().catch(() => ({ error: `HTTP ${response.status}` }));
+            throw new Error((body as { error?: string }).error || `Remote node returned ${response.status}`);
+        }
+
+        const body = await response.json() as { result?: string };
+        return body.result || 'Remote auto-update completed (no details returned).';
+    }
+
     private async executeUpdateForStack(
         stackName: string,
         nodeId: number,
@@ -410,7 +446,7 @@ export class SchedulerService {
     ): Promise<string> {
         const containers = await docker.getContainersByStack(stackName);
         if (!containers || containers.length === 0) {
-            return `Stack "${stackName}": no containers found — skipped.`;
+            return `Stack "${stackName}": no containers found; skipped.`;
         }
 
         const imageRefs = [...new Set(
@@ -420,7 +456,7 @@ export class SchedulerService {
         )];
 
         if (imageRefs.length === 0) {
-            return `Stack "${stackName}": no pullable images — skipped.`;
+            return `Stack "${stackName}": no pullable images; skipped.`;
         }
 
         let hasUpdate = false;