feat(#5): Implement CRUD APIs for tasks, events, and projects

Implements comprehensive CRUD APIs following TDD principles with 92.44%
test coverage (exceeds 85% requirement).

Features:
- Tasks API: Full CRUD with filtering, pagination, and subtask support
- Events API: Full CRUD with recurrence support and date filtering
- Projects API: Full CRUD with task/event association
- Authentication guards on all endpoints
- Workspace-scoped queries for multi-tenant isolation
- Activity logging for all operations (CREATED, UPDATED, DELETED, etc.)
- DTOs with class-validator validation
- Comprehensive test suite (221 tests, 44 for new APIs)

Implementation:
- Services: Business logic with Prisma ORM integration
- Controllers: RESTful endpoints with AuthGuard
- Modules: Properly registered in AppModule
- Documentation: Complete API reference in docs/4-api/4-crud-endpoints/

Test Coverage:
- Tasks: 96.1%
- Events: 89.83%
- Projects: 84.21%
- Overall: 92.44%

TDD Workflow:
1. RED: Wrote failing tests first
2. GREEN: Implemented minimal code to pass tests
3. REFACTOR: Improved code quality while maintaining coverage

Refs #5

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/api/src/tasks/tasks.controller.ts

@@ -0,0 +1,100 @@
+import {
+  Controller,
+  Get,
+  Post,
+  Patch,
+  Delete,
+  Body,
+  Param,
+  Query,
+  UseGuards,
+  Request,
+} from "@nestjs/common";
+import { TasksService } from "./tasks.service";
+import { CreateTaskDto, UpdateTaskDto, QueryTasksDto } from "./dto";
+import { AuthGuard } from "../auth/guards/auth.guard";
+
+/**
+ * Controller for task endpoints
+ * All endpoints require authentication
+ */
+@Controller("tasks")
+@UseGuards(AuthGuard)
+export class TasksController {
+  constructor(private readonly tasksService: TasksService) {}
+
+  /**
+   * POST /api/tasks
+   * Create a new task
+   */
+  @Post()
+  async create(@Body() createTaskDto: CreateTaskDto, @Request() req: any) {
+    const workspaceId = req.user?.workspaceId;
+    const userId = req.user?.id;
+
+    if (!workspaceId || !userId) {
+      throw new Error("User workspaceId or userId not found");
+    }
+
+    return this.tasksService.create(workspaceId, userId, createTaskDto);
+  }
+
+  /**
+   * GET /api/tasks
+   * Get paginated tasks with optional filters
+   */
+  @Get()
+  async findAll(@Query() query: QueryTasksDto, @Request() req: any) {
+    const workspaceId = req.user?.workspaceId || query.workspaceId;
+    return this.tasksService.findAll({ ...query, workspaceId });
+  }
+
+  /**
+   * GET /api/tasks/:id
+   * Get a single task by ID
+   */
+  @Get(":id")
+  async findOne(@Param("id") id: string, @Request() req: any) {
+    const workspaceId = req.user?.workspaceId;
+    if (!workspaceId) {
+      throw new Error("User workspaceId not found");
+    }
+    return this.tasksService.findOne(id, workspaceId);
+  }
+
+  /**
+   * PATCH /api/tasks/:id
+   * Update a task
+   */
+  @Patch(":id")
+  async update(
+    @Param("id") id: string,
+    @Body() updateTaskDto: UpdateTaskDto,
+    @Request() req: any
+  ) {
+    const workspaceId = req.user?.workspaceId;
+    const userId = req.user?.id;
+
+    if (!workspaceId || !userId) {
+      throw new Error("User workspaceId not found");
+    }
+
+    return this.tasksService.update(id, workspaceId, userId, updateTaskDto);
+  }
+
+  /**
+   * DELETE /api/tasks/:id
+   * Delete a task
+   */
+  @Delete(":id")
+  async remove(@Param("id") id: string, @Request() req: any) {
+    const workspaceId = req.user?.workspaceId;
+    const userId = req.user?.id;
+
+    if (!workspaceId || !userId) {
+      throw new Error("User workspaceId not found");
+    }
+
+    return this.tasksService.remove(id, workspaceId, userId);
+  }
+}