fix(desktop): align haha-oauth handler with sibling error-handling convention

Code review follow-up on 142eb9cd:
- 加 outer try/catch + errorResponse wrapper (parity with providers.ts)
- 400 响应改用 ApiError.badRequest (shape 跟其他 handler 一致: {error: 'BAD_REQUEST', message})
- test 加上对 error shape 的断言

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/server/__tests__/haha-oauth-api.test.ts

@@ -64,6 +64,8 @@ describe('POST /api/haha-oauth/start', () => {
     const { req, url, segments } = buildReq('POST', '/api/haha-oauth/start', {})
     const res = await handleHahaOAuthApi(req, url, segments)
     expect(res.status).toBe(400)
+    const body = (await res.json()) as { error: string; message?: string }
+    expect(body.error).toBe('BAD_REQUEST')
   })
 })
 

src/server/api/haha-oauth.ts

@@ -10,6 +10,7 @@
 
 import { z } from 'zod'
 import { hahaOAuthService } from '../services/hahaOAuthService.js'
+import { ApiError, errorResponse } from '../middleware/errorHandler.js'
 
 const StartRequestSchema = z.object({
   serverPort: z.number().int().positive(),
@@ -27,6 +28,7 @@ export async function handleHahaOAuthApi(
   url: URL,
   segments: string[],
 ): Promise<Response> {
+  try {
     const action = segments[2] // segments: ['api', 'haha-oauth', <action?>]
 
     if (action === 'start' && req.method === 'POST') {
@@ -34,14 +36,11 @@ export async function handleHahaOAuthApi(
       try {
         body = await req.json()
       } catch {
-      return Response.json({ error: 'Invalid JSON body' }, { status: 400 })
+        throw ApiError.badRequest('Invalid JSON body')
       }
       const parsed = StartRequestSchema.safeParse(body)
       if (!parsed.success) {
-      return Response.json(
+        throw ApiError.badRequest('serverPort (positive integer) required')
-        { error: 'serverPort (positive integer) required' },
-        { status: 400 },
-      )
       }
       const session = hahaOAuthService.startSession({
         serverPort: parsed.data.serverPort,
@@ -92,6 +91,9 @@ export async function handleHahaOAuthApi(
     }
 
     return Response.json({ error: 'Not Found' }, { status: 404 })
+  } catch (error) {
+    return errorResponse(error)
+  }
 }
 
 function renderCallbackPage(success: boolean, errorMsg: string | null): string {