chore(repo): restructure as monorepo with server and client workspaces

- move NestJS app into server/ subdirectory
- add client/ React+TypeScript (Vite) app with Hello World
- update docker-compose to build and run both services
- add root package.json declaring npm workspaces
- update .gitignore to cover node_modules and dist at all depths

server/src/main.ts

@@ -0,0 +1,45 @@
+import { NestFactory } from "@nestjs/core";
+import { ConfigService } from "@nestjs/config";
+import { AppConfig } from "./config/app.config";
+import { ValidationPipe } from "@nestjs/common";
+import { TraceLogger } from "./common/trace-logger";
+import { DocumentBuilder, SwaggerModule } from "@nestjs/swagger";
+import { AppModule } from "./app.module";
+import { HttpExceptionFilter } from "./filters/http-exception.filter";
+import { TraceInterceptor } from "./interceptors/trace.interceptor";
+import { LoggingInterceptor } from "./interceptors/logging.interceptor";
+import { name as pkgName, version as pkgVersion } from "../package.json";
+
+async function bootstrap() {
+  const logger = new TraceLogger("Bootstrap");
+  const app = await NestFactory.create(AppModule, {
+    logger: new TraceLogger("Bootstrap", { timestamp: true }),
+  });
+
+  app.useGlobalPipes(new ValidationPipe({ transform: true }));
+  app.useGlobalFilters(new HttpExceptionFilter());
+  app.useGlobalInterceptors(new TraceInterceptor(), new LoggingInterceptor());
+
+  const config = app.get<ConfigService<AppConfig, true>>(ConfigService);
+  const port = config.get("PORT");
+  const nodeEnv = config.get("NODE_ENV");
+
+  const swaggerConfig = new DocumentBuilder()
+    .setTitle(pkgName)
+    .setDescription(`${pkgName} API`)
+    .setVersion(pkgVersion)
+    .build();
+
+  const document = SwaggerModule.createDocument(app, swaggerConfig);
+  SwaggerModule.setup("api", app, document);
+
+  await app.listen(port);
+
+  logger.log(
+    `Application "${pkgName}" v${pkgVersion} running on port ${port} [${nodeEnv}]`,
+  );
+  logger.log(`Swagger UI available at http://localhost:${port}/api`);
+  logger.log(`MCP endpoint available at http://localhost:${port}/mcp`);
+}
+
+bootstrap();