feat: automatic worker restart on version updates

Critical improvement for seamless upgrades across all versions.

Changes:
1. Added /api/version endpoint to worker service
   - Returns current worker version from package.json

2. Added version checking in worker-utils.ts
   - getPluginVersion() - reads plugin's package.json version
   - getWorkerVersion() - fetches version from worker API
   - ensureWorkerVersionMatches() - compares and restarts if needed

3. Modified ensureWorkerRunning()
   - Now calls ensureWorkerVersionMatches() after health check
   - Automatically restarts worker when version mismatch detected
   - Logs version mismatch for debugging

Impact:
- Users no longer need to manually restart worker after upgrades
- Eliminates connection errors from running old worker code
- Critical for v7.1.1 (Bun auto-install) and all future releases
- Fixes the issue where PR #236 changes weren't applied until manual restart

Testing:
- Version endpoint working: returns {"version":"7.1.0"}
- Worker health check: passing
- Auto-restart logic: triggers on version mismatch

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

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

src/services/worker-service.ts

@@ -132,6 +132,22 @@ export class WorkerService {
       res.status(200).json({ status: 'ok' });
     });
 
+    // Version endpoint - returns the worker's current version
+    this.app.get('/api/version', (_req, res) => {
+      try {
+        // Read version from marketplace package.json
+        const { homedir } = require('os');
+        const { readFileSync } = require('fs');
+        const marketplaceRoot = path.join(homedir(), '.claude', 'plugins', 'marketplaces', 'thedotmack');
+        const packageJsonPath = path.join(marketplaceRoot, 'package.json');
+        const packageJson = JSON.parse(readFileSync(packageJsonPath, 'utf-8'));
+        res.status(200).json({ version: packageJson.version });
+      } catch (error) {
+        logger.error('SYSTEM', 'Failed to read version', {}, error as Error);
+        res.status(500).json({ error: 'Failed to read version' });
+      }
+    });
+
     // Admin endpoints for process management
     this.app.post('/api/admin/restart', async (_req, res) => {
       res.json({ status: 'restarting' });