fix(lint): resolve line length violations in main.py

- Split long error message strings to meet 88 character limit
- Maintain readability while conforming to flake8 standards
- Fix file upload validation error messages

backend/app/main.py

@@ -354,7 +354,10 @@ async def upload_unit_file(file: UploadFile = File(...)):
         if file.size and file.size > settings.max_upload_size:
             raise HTTPException(
                 status_code=413,
-                detail=f"File too large. Maximum size is {settings.max_upload_size} bytes"
+                detail=(
+                    f"File too large. Maximum size is "
+                    f"{settings.max_upload_size} bytes"
+                ),
             )
 
         # Check file extension
@@ -363,7 +366,10 @@ async def upload_unit_file(file: UploadFile = File(...)):
             if file_ext not in settings.allowed_extensions:
                 raise HTTPException(
                     status_code=400,
-                    detail=f"File type not allowed. Allowed types: {', '.join(settings.allowed_extensions)}"
+                    detail=(
+                        f"File type not allowed. Allowed types: "
+                        f"{', '.join(settings.allowed_extensions)}"
+                    ),
                 )
 
         content = await file.read()
@@ -425,7 +431,7 @@ async def get_info():
             "api_docs": settings.api_docs_enabled,
             "swagger_ui": settings.swagger_ui_enabled,
             "redoc": settings.redoc_enabled,
-        }
+        },
     }
 
 
@@ -441,7 +447,7 @@ async def health_check():
         "service": settings.app_name.lower(),
         "version": settings.app_version,
         "environment": settings.environment,
-        "timestamp": __import__("datetime").datetime.utcnow().isoformat()
+        "timestamp": __import__("datetime").datetime.utcnow().isoformat(),
     }