feat: 原生系统提示词只读展示、会话末尾 fork、深浅色主题

apps/desktop/src/main/ipc.ts

@@ -178,19 +178,25 @@ export function registerIpc(): AgentService {
     )
   })
 
+  // 会话末尾分叉为新会话（pi fork，原会话保留）
+  ipcMain.handle('session:fork', () => pass(() => service.forkSession()))
+
   // ---- 应用设置 ----
   ipcMain.handle('settings:get', () => service.getSettings())
 
-  ipcMain.handle('settings:setPrompt', (_event, text: unknown) => {
-    if (typeof text !== 'string') throw new Error('invalid prompt')
-    return pass(() => service.setSystemPrompt(text))
-  })
+  // 当前生效的系统提示词（pi 原生 + 技能注入，只读展示）
+  ipcMain.handle('settings:getSystemPrompt', () => service.getSystemPrompt())
 
   ipcMain.handle('settings:setTheme', (_event, id: unknown) => {
     if (typeof id !== 'string' || !id.trim()) throw new Error('invalid theme id')
     service.setThemeColor(id.trim())
   })
 
+  ipcMain.handle('settings:setThemeMode', (_event, mode: unknown) => {
+    if (mode !== 'light' && mode !== 'dark' && mode !== 'system') throw new Error('invalid theme mode')
+    service.setThemeMode(mode)
+  })
+
   // ---- 工作区 ----
   ipcMain.handle('workspaces:list', () =>
     service.listWorkspaces().catch((err: unknown) => {