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/environment/environment.controller.ts

@@ -0,0 +1,67 @@
+import {
+  Body,
+  Controller,
+  Delete,
+  Get,
+  HttpCode,
+  Param,
+  ParseIntPipe,
+  Patch,
+  Post,
+  Query,
+} from "@nestjs/common";
+import { ApiOperation, ApiResponse, ApiTags } from "@nestjs/swagger";
+import { EnvironmentService } from "./environment.service";
+import { CreateEnvironmentDto } from "./dto/create-environment.dto";
+import { UpdateEnvironmentDto } from "./dto/update-environment.dto";
+import { PaginationQueryDto } from "../common/dto/pagination.dto";
+import { EnvironmentOrderBy } from "./environment.service";
+
+@ApiTags("environments")
+@Controller("environments")
+export class EnvironmentController {
+  constructor(private readonly environmentService: EnvironmentService) {}
+
+  @Post()
+  @ApiOperation({ summary: "Create a new environment" })
+  @ApiResponse({ status: 201, description: "Environment created" })
+  @ApiResponse({ status: 409, description: "Environment name already exists" })
+  create(@Body() dto: CreateEnvironmentDto) {
+    return this.environmentService.create(dto);
+  }
+
+  @Get()
+  @ApiOperation({ summary: "List all environments (paginated)" })
+  @ApiResponse({ status: 200, description: "Paginated environments" })
+  findAll(@Query() query: PaginationQueryDto<EnvironmentOrderBy>) {
+    return this.environmentService.findAll(query);
+  }
+
+  @Get(":id")
+  @ApiOperation({ summary: "Get environment by ID" })
+  @ApiResponse({ status: 200, description: "Environment record" })
+  @ApiResponse({ status: 404, description: "Environment not found" })
+  findOne(@Param("id", ParseIntPipe) id: number) {
+    return this.environmentService.findOne(id);
+  }
+
+  @Patch(":id")
+  @ApiOperation({ summary: "Update an environment" })
+  @ApiResponse({ status: 200, description: "Environment updated" })
+  @ApiResponse({ status: 404, description: "Environment not found" })
+  update(
+    @Param("id", ParseIntPipe) id: number,
+    @Body() dto: UpdateEnvironmentDto,
+  ) {
+    return this.environmentService.update(id, dto);
+  }
+
+  @Delete(":id")
+  @HttpCode(204)
+  @ApiOperation({ summary: "Delete an environment" })
+  @ApiResponse({ status: 204, description: "Environment deleted" })
+  @ApiResponse({ status: 404, description: "Environment not found" })
+  remove(@Param("id", ParseIntPipe) id: number) {
+    return this.environmentService.remove(id);
+  }
+}