refactor(backend): incremental architecture evolution (Task 19)

- Add common/ layer for shared capabilities (LLM, RAG, document, middleware)
- Add legacy/ layer for existing business code
- Move files to new structure (controllers, routes, services)
- Update index.ts for new route registration
- System remains fully functional

backend/src/legacy/controllers/projectController.ts

@@ -0,0 +1,183 @@
+import { FastifyRequest, FastifyReply } from 'fastify';
+import { projectService } from '../services/projectService.js';
+
+interface ProjectParams {
+  id: string;
+}
+
+interface CreateProjectBody {
+  name: string;
+  background: string;
+  researchType: 'observational' | 'interventional';
+}
+
+interface UpdateProjectBody {
+  name?: string;
+  background?: string;
+  researchType?: 'observational' | 'interventional';
+}
+
+class ProjectController {
+  // 获取项目列表
+  async getProjects(request: FastifyRequest, reply: FastifyReply) {
+    try {
+      // TODO: 从JWT token中获取真实的userId
+      // 目前使用模拟用户ID
+      const userId = 'user-mock-001';
+
+      const projects = await projectService.getProjectsByUserId(userId);
+
+      return reply.code(200).send({
+        success: true,
+        data: projects,
+      });
+    } catch (error) {
+      request.log.error(error);
+      return reply.code(500).send({
+        success: false,
+        message: '获取项目列表失败',
+        error: error instanceof Error ? error.message : 'Unknown error',
+      });
+    }
+  }
+
+  // 获取单个项目详情
+  async getProjectById(
+    request: FastifyRequest<{ Params: ProjectParams }>,
+    reply: FastifyReply
+  ) {
+    try {
+      const { id } = request.params;
+      const userId = 'user-mock-001'; // TODO: 从JWT获取
+
+      const project = await projectService.getProjectById(id, userId);
+
+      if (!project) {
+        return reply.code(404).send({
+          success: false,
+          message: '项目不存在或无权访问',
+        });
+      }
+
+      return reply.code(200).send({
+        success: true,
+        data: project,
+      });
+    } catch (error) {
+      request.log.error(error);
+      return reply.code(500).send({
+        success: false,
+        message: '获取项目详情失败',
+        error: error instanceof Error ? error.message : 'Unknown error',
+      });
+    }
+  }
+
+  // 创建项目
+  async createProject(request: FastifyRequest, reply: FastifyReply) {
+    try {
+      const body = request.body as CreateProjectBody;
+      const userId = 'user-mock-001'; // TODO: 从JWT获取
+
+      // 检查用户项目数量限制（可选）
+      const projectCount = await projectService.countUserProjects(userId);
+      const MAX_PROJECTS = 50; // 可以配置到环境变量
+
+      if (projectCount >= MAX_PROJECTS) {
+        return reply.code(400).send({
+          success: false,
+          message: `最多只能创建${MAX_PROJECTS}个项目`,
+        });
+      }
+
+      const project = await projectService.createProject({
+        name: body.name,
+        background: body.background,
+        researchType: body.researchType,
+        userId,
+      });
+
+      return reply.code(201).send({
+        success: true,
+        message: '项目创建成功',
+        data: project,
+      });
+    } catch (error) {
+      request.log.error(error);
+      return reply.code(500).send({
+        success: false,
+        message: '创建项目失败',
+        error: error instanceof Error ? error.message : 'Unknown error',
+      });
+    }
+  }
+
+  // 更新项目
+  async updateProject(
+    request: FastifyRequest<{ Params: ProjectParams }>,
+    reply: FastifyReply
+  ) {
+    try {
+      const { id } = request.params;
+      const body = request.body as UpdateProjectBody;
+      const userId = 'user-mock-001'; // TODO: 从JWT获取
+
+      const project = await projectService.updateProject(id, userId, body);
+
+      if (!project) {
+        return reply.code(404).send({
+          success: false,
+          message: '项目不存在或无权访问',
+        });
+      }
+
+      return reply.code(200).send({
+        success: true,
+        message: '项目更新成功',
+        data: project,
+      });
+    } catch (error) {
+      request.log.error(error);
+      return reply.code(500).send({
+        success: false,
+        message: '更新项目失败',
+        error: error instanceof Error ? error.message : 'Unknown error',
+      });
+    }
+  }
+
+  // 删除项目
+  async deleteProject(
+    request: FastifyRequest<{ Params: ProjectParams }>,
+    reply: FastifyReply
+  ) {
+    try {
+      const { id } = request.params;
+      const userId = 'user-mock-001'; // TODO: 从JWT获取
+
+      const project = await projectService.deleteProject(id, userId);
+
+      if (!project) {
+        return reply.code(404).send({
+          success: false,
+          message: '项目不存在或无权访问',
+        });
+      }
+
+      return reply.code(200).send({
+        success: true,
+        message: '项目删除成功',
+      });
+    } catch (error) {
+      request.log.error(error);
+      return reply.code(500).send({
+        success: false,
+        message: '删除项目失败',
+        error: error instanceof Error ? error.message : 'Unknown error',
+      });
+    }
+  }
+}
+
+export const projectController = new ProjectController();
+