feat: Add stale process monitor, users route, landing page, archive old scripts

- Add backend stale process monitoring API (/api/stale-processes)
- Add users management route
- Add frontend landing page and stale process monitor UI on /scraper-tools
- Move old development scripts to backend/archive/
- Update frontend build with new features

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

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

backend/archive/cancel-pending-job.js

@@ -0,0 +1,23 @@
+const { Pool } = require('pg');
+
+const pool = new Pool({
+  connectionString: process.env.DATABASE_URL || 'postgresql://kelly:kelly@localhost:5432/hub'
+});
+
+(async () => {
+  try {
+    await pool.query(`
+      UPDATE proxy_test_jobs
+      SET status = 'cancelled',
+          completed_at = CURRENT_TIMESTAMP,
+          updated_at = CURRENT_TIMESTAMP
+      WHERE id = 2
+    `);
+
+    console.log('✅ Cancelled job ID 2');
+    process.exit(0);
+  } catch (error) {
+    console.error('Error:', error);
+    process.exit(1);
+  }
+})();