feat: 웹사이트 표준화 검사 도구 구현

- 4개 검사 엔진: HTML/CSS, 접근성(WCAG), SEO, 성능/보안 (총 50개 항목)
- FastAPI 백엔드 (9개 API, SSE 실시간 진행, PDF/JSON 리포트)
- Next.js 15 프론트엔드 (6개 페이지, 29개 컴포넌트, 반원 게이지 차트)
- Docker Compose 배포 (Backend:8011, Frontend:3011, MongoDB:27022, Redis:6392)
- 전체 테스트 32/32 PASS

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/lib/api.ts

@@ -0,0 +1,148 @@
+import type {
+  StartInspectionResponse,
+  InspectionResult,
+  IssueListResponse,
+  IssueFilters,
+  PaginatedResponse,
+  HistoryParams,
+  TrendResponse,
+} from "@/types/inspection";
+
+const API_BASE_URL =
+  process.env.NEXT_PUBLIC_API_URL || "http://localhost:8011";
+
+/** API 에러 클래스 */
+export class ApiError extends Error {
+  status: number;
+  detail: string;
+
+  constructor(status: number, detail: string) {
+    super(detail);
+    this.name = "ApiError";
+    this.status = status;
+    this.detail = detail;
+  }
+}
+
+/** API 클라이언트 */
+class ApiClient {
+  private baseUrl: string;
+
+  constructor(baseUrl: string) {
+    this.baseUrl = baseUrl;
+  }
+
+  private async request<T>(path: string, options?: RequestInit): Promise<T> {
+    const response = await fetch(`${this.baseUrl}${path}`, {
+      headers: { "Content-Type": "application/json" },
+      ...options,
+    });
+
+    if (!response.ok) {
+      let detail = "요청 처리 중 오류가 발생했습니다";
+      try {
+        const error = await response.json();
+        detail = error.detail || detail;
+      } catch {
+        // JSON 파싱 실패 시 기본 메시지 사용
+      }
+      throw new ApiError(response.status, detail);
+    }
+
+    return response.json();
+  }
+
+  /** 검사 시작 */
+  async startInspection(url: string): Promise<StartInspectionResponse> {
+    return this.request("/api/inspections", {
+      method: "POST",
+      body: JSON.stringify({ url }),
+    });
+  }
+
+  /** 검사 결과 조회 */
+  async getInspection(id: string): Promise<InspectionResult> {
+    return this.request(`/api/inspections/${id}`);
+  }
+
+  /** 이슈 목록 조회 */
+  async getIssues(
+    id: string,
+    filters?: IssueFilters
+  ): Promise<IssueListResponse> {
+    const params = new URLSearchParams();
+    if (filters?.category && filters.category !== "all") {
+      params.set("category", filters.category);
+    }
+    if (filters?.severity && filters.severity !== "all") {
+      params.set("severity", filters.severity);
+    }
+    const qs = params.toString();
+    return this.request(`/api/inspections/${id}/issues${qs ? `?${qs}` : ""}`);
+  }
+
+  /** 이력 목록 조회 (페이지네이션) */
+  async getInspections(params: HistoryParams): Promise<PaginatedResponse> {
+    const qs = new URLSearchParams();
+    qs.set("page", String(params.page || 1));
+    qs.set("limit", String(params.limit || 20));
+    if (params.url) qs.set("url", params.url);
+    if (params.sort) qs.set("sort", params.sort);
+    return this.request(`/api/inspections?${qs}`);
+  }
+
+  /** 트렌드 데이터 조회 */
+  async getTrend(url: string, limit = 10): Promise<TrendResponse> {
+    const qs = new URLSearchParams({ url, limit: String(limit) });
+    return this.request(`/api/inspections/trend?${qs}`);
+  }
+
+  /** PDF 다운로드 */
+  async downloadPdf(id: string): Promise<void> {
+    const response = await fetch(
+      `${this.baseUrl}/api/inspections/${id}/report/pdf`
+    );
+    if (!response.ok) {
+      throw new ApiError(response.status, "PDF 다운로드에 실패했습니다");
+    }
+    const blob = await response.blob();
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download =
+      response.headers.get("content-disposition")?.split("filename=")[1] ||
+      `web-inspector-report.pdf`;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    URL.revokeObjectURL(url);
+  }
+
+  /** JSON 다운로드 */
+  async downloadJson(id: string): Promise<void> {
+    const response = await fetch(
+      `${this.baseUrl}/api/inspections/${id}/report/json`
+    );
+    if (!response.ok) {
+      throw new ApiError(response.status, "JSON 다운로드에 실패했습니다");
+    }
+    const blob = await response.blob();
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download =
+      response.headers.get("content-disposition")?.split("filename=")[1] ||
+      `web-inspector-report.json`;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    URL.revokeObjectURL(url);
+  }
+
+  /** SSE 스트림 URL 반환 */
+  getStreamUrl(inspectionId: string): string {
+    return `${this.baseUrl}/api/inspections/${inspectionId}/stream`;
+  }
+}
+
+export const api = new ApiClient(API_BASE_URL);