feat: add tray support and cross-platform packaging assets (v0.9.6)

- Generate placeholder icons: icon.png (512x512), tray-icon.png (16x16), icon.icns (macOS)
- Fix window close behavior: hide to tray instead of quitting
- Add tray left-click and double-click handlers to restore window
- Add app.dock.hide/show on macOS for proper dock visibility
- Bump version to 0.9.6 in package.json, preload.js, openclaw-manager.js

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

preload.js

@@ -7,6 +7,6 @@ const { contextBridge } = require('electron');
 
 contextBridge.exposeInMainWorld('odo', {
   platform: process.platform,
-  version: '0.9.4',
+  version: '0.9.6',
   isElectron: true
 });