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/src/api/workflows.js

@@ -45,6 +45,11 @@ import {
   createWorkflowBackupBuffer,
   restoreWorkflowBackup,
 } from "../../workflow-backup.js";
+import {
+  listExampleWorkflows,
+  readExampleWorkflow,
+  assertExampleWorkflowId,
+} from "../../workflow-examples.js";
 
 /**
  * Reload this process and notify other HTTP/worker processes via Redis.
@@ -246,6 +251,22 @@ export default function workflowsPluginFactory(registry) {
       return { owners: fsStore.listOwners() };
     });
 
+    fastify.get("/workflow-examples", async () => {
+      return { examples: listExampleWorkflows() };
+    });
+
+    fastify.get("/workflow-examples/:id", async (req, reply) => {
+      const { id } = /** @type {{ id: string }} */ (req.params);
+      if (!assertExampleWorkflowId(id)) {
+        return reply.code(400).send({ error: "invalid example id" });
+      }
+      const example = readExampleWorkflow(id);
+      if (!example) {
+        return reply.code(404).send({ error: "example not found" });
+      }
+      return example;
+    });
+
     fastify.get("/workflows/trash", async () => {
       return { items: await listTrash() };
     });