feat: scaffold monorepo with shared types and NestJS server

- pnpm workspace with packages/app, packages/server, packages/shared
- @mp-pilates/shared: enums, constants, TypeScript interfaces for all 8 data models
- @mp-pilates/server: NestJS bootstrap with health check, validation pipe, CORS
- Base TypeScript config with strict mode

packages/server/src/app.controller.ts

@@ -0,0 +1,9 @@
+import { Controller, Get } from '@nestjs/common'
+
+@Controller()
+export class AppController {
+  @Get('health')
+  health() {
+    return { status: 'ok', timestamp: new Date().toISOString() }
+  }
+}

packages/server/src/app.module.ts

@@ -0,0 +1,14 @@
+import { Module } from '@nestjs/common'
+import { ConfigModule } from '@nestjs/config'
+import { AppController } from './app.controller'
+
+@Module({
+  imports: [
+    ConfigModule.forRoot({
+      isGlobal: true,
+      envFilePath: ['.env.local', '.env'],
+    }),
+  ],
+  controllers: [AppController],
+})
+export class AppModule {}

packages/server/src/main.ts

@@ -0,0 +1,24 @@
+import { NestFactory } from '@nestjs/core'
+import { ValidationPipe } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
+import { AppModule } from './app.module'
+
+async function bootstrap() {
+  const app = await NestFactory.create(AppModule)
+  const configService = app.get(ConfigService)
+
+  app.setGlobalPrefix('api')
+  app.useGlobalPipes(
+    new ValidationPipe({
+      whitelist: true,
+      forbidNonWhitelisted: true,
+      transform: true,
+    }),
+  )
+  app.enableCors()
+
+  const port = configService.get<number>('PORT', 3000)
+  await app.listen(port)
+  console.log(`Server running on http://localhost:${port}`)
+}
+bootstrap()