feat(core): initialize project skeleton with Electron + React + TypeScript

Set up the complete project foundation for ClawX, a graphical AI assistant:

- Electron main process with IPC handlers, menu, tray, and gateway management
- React renderer with routing, layout components, and page scaffolding
- Zustand state management for gateway, settings, channels, skills, chat, and cron
- shadcn/ui components with Tailwind CSS and CSS variable theming
- Build tooling with Vite, electron-builder, and TypeScript configuration
- Testing setup with Vitest and Playwright
- Development configurations (ESLint, Prettier, gitignore, env example)

.env.example

@@ -0,0 +1,20 @@
+# ClawX Environment Variables
+
+# OpenClaw Gateway Configuration
+OPENCLAW_GATEWAY_PORT=18789
+
+# Development Configuration
+VITE_DEV_SERVER_PORT=5173
+
+# Release Configuration (CI/CD)
+# Apple Developer Credentials
+APPLE_ID=your@email.com
+APPLE_APP_SPECIFIC_PASSWORD=xxxx-xxxx-xxxx-xxxx
+APPLE_TEAM_ID=XXXXXXXXXX
+
+# Code Signing Certificate
+CSC_LINK=path/to/certificate.p12
+CSC_KEY_PASSWORD=certificate_password
+
+# GitHub Token for releases
+GH_TOKEN=github_personal_access_token