feat(workflows): migrate legacy workflows and enhance example handling

- Migrated legacy workflow files from `packages/server/workflows/` to `packages/server/data/workflows/` when the new store is empty.
- Introduced new API endpoints to list and retrieve example workflows.
- Added a dialog component for selecting example workflows when creating new workflows.
- Updated workflow paths and configurations to reflect the new structure.
- Enhanced the README and AGENTS.md documentation to clarify workflow management and usage.

Co-authored-by: Nasyarobby Putra <nasyarobby@gmail.com>

packages/server/start-app.js

@@ -31,6 +31,7 @@ import {
   getRedisUrlForLog,
 } from "./workflow-queue.js";
 import { purgeExpiredTrash } from "./workflow-trash.js";
+import { migrateLegacyWorkflowsIfNeeded } from "./workflow-migrate.js";
 import {
   getConfigGeneration,
   startHeartbeatLoop,
@@ -128,6 +129,12 @@ export async function startApp(opts = {}) {
     }
   });
 
+  try {
+    migrateLegacyWorkflowsIfNeeded();
+  } catch (err) {
+    log.warn({ err }, "legacy workflow migrate failed");
+  }
+
   const registry = createRegistry(server, {
     queue: workflowQueue,
     // Cron + HTTP triggers enqueue jobs; only the API process may own them.