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>

backend/app/services/report_service.py

@@ -0,0 +1,95 @@
+"""
+Report generation service.
+Generates PDF and JSON reports from inspection results.
+"""
+
+import json
+import logging
+from datetime import datetime
+from pathlib import Path
+from typing import Optional
+from urllib.parse import urlparse
+
+from jinja2 import Environment, FileSystemLoader
+from slugify import slugify
+
+logger = logging.getLogger(__name__)
+
+TEMPLATES_DIR = Path(__file__).parent.parent / "templates"
+
+# Grade color mapping
+GRADE_COLORS = {
+    "A+": "#22C55E",
+    "A": "#22C55E",
+    "B": "#3B82F6",
+    "C": "#F59E0B",
+    "D": "#F97316",
+    "F": "#EF4444",
+}
+
+SEVERITY_COLORS = {
+    "critical": "#EF4444",
+    "major": "#F97316",
+    "minor": "#EAB308",
+    "info": "#3B82F6",
+}
+
+CATEGORY_LABELS = {
+    "html_css": "HTML/CSS 표준",
+    "accessibility": "접근성 (WCAG)",
+    "seo": "SEO 최적화",
+    "performance_security": "성능/보안",
+}
+
+
+class ReportService:
+    """PDF and JSON report generation service."""
+
+    def __init__(self):
+        self.env = Environment(
+            loader=FileSystemLoader(str(TEMPLATES_DIR)),
+            autoescape=True,
+        )
+        # Register custom filters
+        self.env.filters["grade_color"] = lambda g: GRADE_COLORS.get(g, "#6B7280")
+        self.env.filters["severity_color"] = lambda s: SEVERITY_COLORS.get(s, "#6B7280")
+        self.env.filters["category_label"] = lambda c: CATEGORY_LABELS.get(c, c)
+
+    async def generate_pdf(self, inspection: dict) -> bytes:
+        """Generate PDF report from inspection result."""
+        try:
+            from weasyprint import HTML
+
+            template = self.env.get_template("report.html")
+            html_string = template.render(
+                inspection=inspection,
+                generated_at=datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC"),
+                grade_colors=GRADE_COLORS,
+                severity_colors=SEVERITY_COLORS,
+                category_labels=CATEGORY_LABELS,
+            )
+            pdf_bytes = HTML(string=html_string).write_pdf()
+            return pdf_bytes
+
+        except ImportError:
+            logger.error("WeasyPrint is not installed")
+            raise RuntimeError("PDF generation is not available (WeasyPrint not installed)")
+        except Exception as e:
+            logger.error("PDF generation failed: %s", str(e))
+            raise RuntimeError(f"PDF generation failed: {str(e)}")
+
+    async def generate_json(self, inspection: dict) -> bytes:
+        """Generate JSON report from inspection result."""
+        # Remove MongoDB internal fields
+        clean_data = {k: v for k, v in inspection.items() if k != "_id"}
+        json_str = json.dumps(clean_data, ensure_ascii=False, indent=2, default=str)
+        return json_str.encode("utf-8")
+
+    @staticmethod
+    def generate_filename(url: str, extension: str) -> str:
+        """Generate download filename: web-inspector-{url-slug}-{date}.{ext}"""
+        parsed = urlparse(url)
+        hostname = parsed.hostname or "unknown"
+        url_slug = slugify(hostname, max_length=50)
+        date_str = datetime.utcnow().strftime("%Y-%m-%d")
+        return f"web-inspector-{url_slug}-{date_str}.{extension}"