fix: Hide console window on Windows when spawning child processes (#166)

* fix: Hide console window on Windows when spawning child processes

Add windowsHide: true to spawnSync and execSync calls to prevent
empty console windows from appearing on Windows when hooks execute.

Fixes two spawn points:
- worker-utils.ts: PM2 spawn when starting worker service
- user-message-hook.ts: Node spawn for context display

Reference: https://nodejs.org/api/child_process.html (windowsHide option)

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

* fix: Add windowsHide to remaining execSync calls for complete Windows console window hiding

This completes the Windows console window fix by adding `windowsHide: true` to all remaining `execSync` calls:

- src/services/worker-service.ts:220 - pgrep command for orphaned process detection
- src/services/worker-service.ts:226 - pkill command for process cleanup
- src/services/worker/SDKAgent.ts:414 - where/which claude command for finding executable

These operations are less frequent than the user-prompt hook, but should still avoid spawning console windows on Windows for a complete fix.

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

Co-authored-by: Alex Newman <thedotmack@users.noreply.github.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: Alex Newman <thedotmack@users.noreply.github.com>

src/shared/worker-utils.ts

@@ -67,7 +67,8 @@ async function startWorker(): Promise<boolean> {
     const result = spawnSync(pm2Command, ['start', ecosystemPath], {
       cwd: pluginRoot,
       stdio: 'pipe',
-      encoding: 'utf-8'
+      encoding: 'utf-8',
+      windowsHide: true
     });
     if (result.status !== 0) {
       throw new Error(result.stderr || 'PM2 start failed');