style: fix all flake8 linter errors across app/ directory

- Run Black formatter and isort on all app/ files
- Remove unused imports (F401) across multiple files
- Add # noqa: F401 for intentional re-exports in celery_worker.py,
  tasks/__init__.py, utils.py, frontend.py, views/base.py
- Fix f-strings without placeholders (F541) in azure.py, notification.py,
  check_credentials.py, upload_to_onedrive.py, settings.py
- Fix bare except (E722) in upload_to_sftp.py
- Fix block comment format (E265) in models.py
- Move imports to top of file to fix E402 in celery_app.py, celery_worker.py
- Fix line-too-long (E501) by wrapping strings in multiple files
- Remove unused variable (F841) in upload_to_nextcloud.py

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/views/onedrive.py

@@ -1,12 +1,14 @@
 """
 OneDrive integration views for setup and OAuth callback.
 """
+
 from fastapi import Request
 
-from app.views.base import APIRouter, templates, require_login, settings
+from app.views.base import APIRouter, require_login, settings, templates
 
 router = APIRouter()
 
+
 @router.get("/onedrive-setup")
 @require_login
 async def onedrive_setup_page(request: Request):
@@ -15,10 +17,10 @@ async def onedrive_setup_page(request: Request):
     Shows configuration status and setup instructions.
     """
     # Check OneDrive configuration
-    is_configured = bool(settings.onedrive_client_id and 
-                         settings.onedrive_client_secret and 
-                         settings.onedrive_refresh_token)
-    
+    is_configured = bool(
+        settings.onedrive_client_id and settings.onedrive_client_secret and settings.onedrive_refresh_token
+    )
+
     # Get configuration values to display status (hide sensitive values)
     return templates.TemplateResponse(
         "onedrive.html",
@@ -32,10 +34,11 @@ async def onedrive_setup_page(request: Request):
             "tenant_id": settings.onedrive_tenant_id,
             "refresh_token": bool(settings.onedrive_refresh_token),
             "refresh_token_value": settings.onedrive_refresh_token if settings.onedrive_refresh_token else "",
-            "folder_path": settings.onedrive_folder_path or "Documents/Uploads"  # Default folder path
-        }
+            "folder_path": settings.onedrive_folder_path or "Documents/Uploads",  # Default folder path
+        },
     )
 
+
 @router.get("/onedrive-callback")
 @require_login
 async def onedrive_callback(request: Request, code: str = None, error: str = None):
@@ -44,25 +47,22 @@ async def onedrive_callback(request: Request, code: str = None, error: str = Non
     Now automatically exchanges the code for a token and saves it to the configuration.
     """
     if error:
-        return templates.TemplateResponse(
-            "onedrive_callback_error.html",
-            {"request": request, "error": error}
-        )
-    
+        return templates.TemplateResponse("onedrive_callback_error.html", {"request": request, "error": error})
+
     if not code:
         return templates.TemplateResponse(
             "onedrive_callback_error.html",
-            {"request": request, "error": "No authorization code received from Microsoft"}
+            {"request": request, "error": "No authorization code received from Microsoft"},
         )
-    
+
     # Display the processing page with automatic token exchange
     return templates.TemplateResponse(
         "onedrive_callback.html",
         {
-            "request": request, 
+            "request": request,
             "code": code,
             "client_id_value": settings.onedrive_client_id or "",
             "client_secret_value": settings.onedrive_client_secret or "",
-            "tenant_id": settings.onedrive_tenant_id or "common"
-        }
+            "tenant_id": settings.onedrive_tenant_id or "common",
+        },
     )