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/cron.ts

@@ -0,0 +1,68 @@
+/**
+ * Cron Job Type Definitions
+ * Types for scheduled tasks
+ */
+
+import { ChannelType } from './channel';
+
+/**
+ * Cron job target (where to send the result)
+ */
+export interface CronJobTarget {
+  channelType: ChannelType;
+  channelId: string;
+  channelName: string;
+}
+
+/**
+ * Cron job last run info
+ */
+export interface CronJobLastRun {
+  time: string;
+  success: boolean;
+  error?: string;
+  duration?: number;
+}
+
+/**
+ * Cron job data structure
+ */
+export interface CronJob {
+  id: string;
+  name: string;
+  message: string;
+  schedule: string;
+  target: CronJobTarget;
+  enabled: boolean;
+  createdAt: string;
+  updatedAt: string;
+  lastRun?: CronJobLastRun;
+  nextRun?: string;
+}
+
+/**
+ * Input for creating a cron job
+ */
+export interface CronJobCreateInput {
+  name: string;
+  message: string;
+  schedule: string;
+  target: CronJobTarget;
+  enabled?: boolean;
+}
+
+/**
+ * Input for updating a cron job
+ */
+export interface CronJobUpdateInput {
+  name?: string;
+  message?: string;
+  schedule?: string;
+  target?: CronJobTarget;
+  enabled?: boolean;
+}
+
+/**
+ * Schedule type for UI picker
+ */
+export type ScheduleType = 'daily' | 'weekly' | 'monthly' | 'interval' | 'custom';