feat: enhance agent execution flow with multi-execution view and improved error handling

- Added multi-execution view to display multiple execution statuses.
- Improved error handling in agent triggering to surface failures.
- Updated execution view to support live updates via SSE and added a log panel for node logs.
- Enhanced pipeline canvas to display node statuses during execution.
- Introduced new fields in the build node form for Docker configurations.
- Updated API to support execution streaming and enhanced node catalog descriptions.

web/lib/api.ts

@@ -161,10 +161,16 @@ export const api = {
 
   triggerAgent: (id: string) =>
     fetch(`${base}/api/agents/${id}/trigger`, { method: "POST" }).then(
-      handle<{ executionIds: string[] }>
+      handle<{
+        executionIds: string[];
+        failures?: { pipelineId: string; reason: string; error?: string }[];
+      }>
     ),
 
   // --- runs ---
+  /** Returns the EventSource URL for SSE streaming of an execution. */
+  executionStreamURL: (id: string) => `${base}/api/executions/${id}/stream`,
+
   listRuns: (params?: { pipelineId?: string; limit?: number }) => {
     const qs = new URLSearchParams();
     if (params?.pipelineId) qs.set("pipeline_id", params.pipelineId);