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)

src/types/gateway.ts

@@ -0,0 +1,25 @@
+/**
+ * Gateway Type Definitions
+ * Types for Gateway communication and data structures
+ */
+
+/**
+ * Gateway connection status
+ */
+export interface GatewayStatus {
+  state: 'stopped' | 'starting' | 'running' | 'error';
+  port: number;
+  pid?: number;
+  uptime?: number;
+  error?: string;
+  connectedAt?: number;
+}
+
+/**
+ * Gateway RPC response
+ */
+export interface GatewayRpcResponse<T = unknown> {
+  success: boolean;
+  result?: T;
+  error?: string;
+}