feat(server): add POST /attachment/box with real-evidence flip + cap

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

app/api/v1/attachment.py

@@ -4,6 +4,8 @@ from sqlalchemy.orm import Session
 from app.core.database import get_db
 from app.models.attachment import AttachmentCategory
 from app.schemas.attachment import (
+    AttachmentBoxSaveRequest,
+    AttachmentBoxSaveResponse,
     AttachmentConfigRequest,
     AttachmentLocationRequest,
     AttachmentLocationResponse,
@@ -15,6 +17,7 @@ from app.services.attachment_service import (
     configure_attachment,
     get_attachment_status,
     register_attachment_location,
+    save_attachment_box,
 )
 
 router = APIRouter(tags=["attachment"])
@@ -64,3 +67,18 @@ def post_attachment_location(
         created_at=record.created_at.isoformat(),
         previous_location=getattr(record, "previous_location", None),
     )
+
+
+@router.post(
+    "/attachment/box",
+    response_model=AttachmentBoxSaveResponse,
+    responses={
+        400: {"description": "参数非法或超量", "model": ErrorResponse},
+        404: {"description": "总排号/类型不存在", "model": ErrorResponse},
+        409: {"description": "同箱同类型重复", "model": ErrorResponse},
+    },
+)
+def post_attachment_box(
+    req: AttachmentBoxSaveRequest, db: Session = Depends(get_db)
+):
+    return save_attachment_box(db, req)