feat(inbox): 素材持久化 CRUD — 数据库表 + API + 前端接入

- 新增 materials 表（id/projectId/description/associatedDate/status/createdAt/updatedAt）
- 新增 4 个后端 API 路由（list/create/get/delete）+ 13 个测试
- 新增 use-materials hooks（TanStack Query）
- 收集箱页面重构为三层架构（InboxPage + MaterialSidebar + MaterialDetailPanel）
- MaterialCard: Popconfirm 删除确认 + 粗粒度时间格式
- MaterialContent: 展示状态标签 + createdAt
- 更新开发文档 backend.md / frontend.md

src/server/routes/materials/list.ts

@@ -0,0 +1,35 @@
+import type Database from "bun:sqlite";
+
+import type { RuntimeMode } from "../../../shared/api";
+import type { Logger } from "../../logger";
+
+import { listMaterials } from "../../db/materials";
+import { createApiError, jsonResponse, parseIdFromUrl } from "../../helpers";
+import { validateIdParam, validatePagination } from "../../middleware";
+
+export function handleListMaterials(req: Request, db: Database, mode: RuntimeMode, _logger: Logger): Response {
+  const url = new URL(req.url);
+  const projectIdStr = parseIdFromUrl(url);
+
+  const validated = validateIdParam(projectIdStr ?? "", mode);
+  if (validated instanceof Response) return validated;
+
+  const pageParam = url.searchParams.get("page");
+  const pageSizeParam = url.searchParams.get("pageSize");
+  const statusParam = url.searchParams.get("status");
+
+  const pagination = validatePagination(pageParam, pageSizeParam, mode);
+  if (pagination instanceof Response) return pagination;
+
+  if (statusParam && statusParam !== "pending" && statusParam !== "approved" && statusParam !== "discarded") {
+    return jsonResponse(createApiError("Invalid status parameter", 400), { mode, status: 400 });
+  }
+
+  const result = listMaterials(db, validated.id, {
+    page: pagination.page,
+    pageSize: pagination.pageSize,
+    status: (statusParam as "approved" | "discarded" | "pending") ?? undefined,
+  });
+
+  return jsonResponse(result, { mode });
+}