fix(identity): Use unique session IDs for proxy rotation + add task pool gate

- Fix buildEvomiProxyUrl to use passed session ID from identity pool
  instead of truncating to worker+region (causing same IP for all workers)
- Add task pool gate feature with database-backed state
- Add /tasks/pool/toggle endpoint and UI toggle button
- Fix isTaskPoolPaused() missing await in claimTask

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/routes/tasks.ts

@@ -49,8 +49,11 @@ function getRequestMetadata(req: Request): Record<string, unknown> {
 import { pool } from '../db/pool';
 import {
   isTaskPoolPaused,
+  isTaskPoolOpen,
   pauseTaskPool,
   resumeTaskPool,
+  closeTaskPool,
+  openTaskPool,
   getTaskPoolStatus,
 } from '../tasks/task-pool-state';
 
@@ -1546,40 +1549,93 @@ router.get('/states', async (_req: Request, res: Response) => {
 
 /**
  * GET /api/tasks/pool/status
- * Check if task pool is paused
+ * Check if task pool is open or closed
  */
 router.get('/pool/status', async (_req: Request, res: Response) => {
-  const status = getTaskPoolStatus();
-  res.json({
-    success: true,
-    ...status,
-  });
+  try {
+    const status = await getTaskPoolStatus();
+    res.json({
+      success: true,
+      ...status,
+    });
+  } catch (err: any) {
+    res.status(500).json({ success: false, error: err.message });
+  }
 });
 
 /**
- * POST /api/tasks/pool/pause
- * Pause the task pool - workers won't pick up new tasks
+ * POST /api/tasks/pool/close
+ * Close the task pool - workers won't pick up new tasks
  */
+router.post('/pool/close', async (_req: Request, res: Response) => {
+  try {
+    await closeTaskPool();
+    res.json({
+      success: true,
+      open: false,
+      message: 'Pool is Closed - workers will not pick up new tasks',
+    });
+  } catch (err: any) {
+    res.status(500).json({ success: false, error: err.message });
+  }
+});
+
+/**
+ * POST /api/tasks/pool/open
+ * Open the task pool - workers will pick up tasks again
+ */
+router.post('/pool/open', async (_req: Request, res: Response) => {
+  try {
+    await openTaskPool();
+    res.json({
+      success: true,
+      open: true,
+      message: 'Pool is Open - workers are picking up tasks',
+    });
+  } catch (err: any) {
+    res.status(500).json({ success: false, error: err.message });
+  }
+});
+
+/**
+ * POST /api/tasks/pool/toggle
+ * Toggle the task pool state
+ */
+router.post('/pool/toggle', async (_req: Request, res: Response) => {
+  try {
+    const isOpen = await isTaskPoolOpen();
+    if (isOpen) {
+      await closeTaskPool();
+    } else {
+      await openTaskPool();
+    }
+    const status = await getTaskPoolStatus();
+    res.json({
+      success: true,
+      ...status,
+    });
+  } catch (err: any) {
+    res.status(500).json({ success: false, error: err.message });
+  }
+});
+
+// Legacy endpoints for compatibility
 router.post('/pool/pause', async (_req: Request, res: Response) => {
-  pauseTaskPool();
-  res.json({
-    success: true,
-    paused: true,
-    message: 'Task pool paused - workers will not pick up new tasks',
-  });
+  try {
+    await closeTaskPool();
+    res.json({ success: true, paused: true, message: 'Task pool closed' });
+  } catch (err: any) {
+    res.status(500).json({ success: false, error: err.message });
+  }
 });
 
-/**
- * POST /api/tasks/pool/resume
- * Resume the task pool - workers will pick up tasks again
- */
 router.post('/pool/resume', async (_req: Request, res: Response) => {
-  resumeTaskPool();
-  res.json({
-    success: true,
-    paused: false,
-    message: 'Task pool resumed - workers will pick up new tasks',
-  });
+  try {
+    await openTaskPool();
+    res.json({ success: true, paused: false, message: 'Task pool opened' });
+  } catch (err: any) {
+    res.status(500).json({ success: false, error: err.message });
+  }
 });
 
 export default router;