feat(server): add auth, user, and studio modules

Auth: WeChat login, JWT, roles guard (24 tests passing)
User: profile CRUD, training stats with month/total calculations
Studio: config management with auto-default creation

packages/server/src/user/user.controller.ts

@@ -0,0 +1,35 @@
+import {
+  Controller,
+  Get,
+  Put,
+  Body,
+  UseGuards,
+} from '@nestjs/common'
+import { JwtAuthGuard } from '../auth/jwt-auth.guard'
+import { CurrentUser } from '../common/decorators/current-user.decorator'
+import { UserService } from './user.service'
+import { UpdateProfileDto } from './dto/update-profile.dto'
+
+@UseGuards(JwtAuthGuard)
+@Controller('user')
+export class UserController {
+  constructor(private readonly userService: UserService) {}
+
+  @Get('profile')
+  getProfile(@CurrentUser('sub') userId: string) {
+    return this.userService.getProfile(userId)
+  }
+
+  @Put('profile')
+  updateProfile(
+    @CurrentUser('sub') userId: string,
+    @Body() dto: UpdateProfileDto,
+  ) {
+    return this.userService.updateProfile(userId, dto)
+  }
+
+  @Get('stats')
+  getStats(@CurrentUser('sub') userId: string) {
+    return this.userService.getStats(userId)
+  }
+}