feat(phase1): architecture skeleton

- Electron 33 main process with frameless window, IPC, win-state persistence
- Preload with contextBridge typed API (window, theme, dialog)
- Vue 3 + Pinia + Element Plus + Vue Router renderer
- Dark/light dual theme via CSS custom properties
- TitleBar with window controls + theme toggle
- StatusBar placeholder
- Design spec document

tsconfig.web.json

@@ -10,5 +10,5 @@
     "lib": ["ESNext", "DOM", "DOM.Iterable"],
     "composite": true
   },
-  "include": ["src/renderer/**/*", "src/renderer/src/**/*.d.ts"]
+  "include": ["src/renderer/**/*", "src/renderer/src/**/*.d.ts", "src/preload/index.d.ts"]
 }