feat: 3-mode inspection with tabbed UI + batch upload

- Add batch inspection backend (multipart upload, SSE streaming, MongoDB)
- Add tabbed UI (single page / site crawling / batch upload) on home and history pages
- Add batch inspection progress, result pages with 2-panel layout
- Rename "사이트 전체" to "사이트 크롤링" across codebase
- Add python-multipart dependency for file upload
- Consolidate nginx SSE location for all inspection types

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

backend/app/models/batch_schemas.py

@@ -0,0 +1,86 @@
+"""
+Pydantic models for batch inspection request/response validation.
+
+Batch inspection allows inspecting multiple URLs from a file upload
+without any crawling phase - URLs are inspected directly.
+"""
+
+from pydantic import BaseModel, Field
+from typing import Optional
+from datetime import datetime
+from enum import Enum
+
+from app.models.site_schemas import AggregateScores, PageStatus
+
+
+# --- Enums ---
+
+class BatchInspectionStatus(str, Enum):
+    """Batch inspection status (no crawling phase)."""
+    INSPECTING = "inspecting"
+    COMPLETED = "completed"
+    ERROR = "error"
+
+
+# --- Core Data Models ---
+
+class BatchPage(BaseModel):
+    """배치 검사 개별 페이지 (크롤링 없이 직접 지정된 URL)."""
+    url: str
+    depth: int = 0
+    parent_url: Optional[str] = None
+    inspection_id: Optional[str] = None
+    status: PageStatus = PageStatus.PENDING
+    title: Optional[str] = None
+    overall_score: Optional[int] = None
+    grade: Optional[str] = None
+
+
+class BatchInspectionConfig(BaseModel):
+    """배치 검사 설정."""
+    concurrency: int = 4
+
+
+# --- Response Models ---
+
+class StartBatchInspectionResponse(BaseModel):
+    """배치 검사 시작 응답."""
+    batch_inspection_id: str
+    status: str = "inspecting"
+    name: str
+    total_urls: int
+    stream_url: str
+
+
+class BatchInspectionResult(BaseModel):
+    """배치 검사 전체 결과."""
+    batch_inspection_id: str
+    name: str
+    status: BatchInspectionStatus
+    created_at: datetime
+    completed_at: Optional[datetime] = None
+    config: BatchInspectionConfig
+    source_urls: list[str] = []
+    discovered_pages: list[BatchPage] = []
+    aggregate_scores: Optional[AggregateScores] = None
+
+
+class BatchInspectionListItem(BaseModel):
+    """배치 검사 목록 항목 (요약)."""
+    batch_inspection_id: str
+    name: str
+    status: BatchInspectionStatus
+    created_at: datetime
+    total_urls: int = 0
+    pages_inspected: int = 0
+    overall_score: Optional[int] = None
+    grade: Optional[str] = None
+
+
+class BatchInspectionPaginatedResponse(BaseModel):
+    """배치 검사 목록 페이지네이션 응답."""
+    items: list[BatchInspectionListItem]
+    total: int
+    page: int
+    limit: int
+    total_pages: int