merge: resolve conflicts with main branch (keep both SharePoint + iCloud integrations)

Merge origin/main into copilot/add-sharepoint-integration.
All four conflicts were resolved by keeping both the SharePoint
additions (from this branch) and the iCloud additions (from main):
- app/models.py: added both SHAREPOINT and ICLOUD to IntegrationType
- app/tasks/send_to_all.py: added both to service_map and services list
- app/tasks/upload_to_user_integration.py: kept both upload handlers
- frontend/templates/files.html: added both filter options

No database migration conflicts — SharePoint does not require schema changes.

app/celery_worker.py

@@ -39,12 +39,14 @@ from app.tasks.refine_text_with_gpt import refine_text_with_gpt  # noqa: F401
 from app.tasks.rotate_pdf_pages import rotate_pdf_pages  # noqa: F401
 from app.tasks.send_to_all import send_to_all_destinations  # noqa: F401
 from app.tasks.subscription_tasks import apply_pending_subscription_changes_all  # noqa: F401
+from app.tasks.translate_to_default_language import translate_to_default_language  # noqa: F401
 
 # Import new send tasks
 from app.tasks.upload_to_dropbox import upload_to_dropbox  # noqa: F401
 from app.tasks.upload_to_email import upload_to_email  # noqa: F401
 from app.tasks.upload_to_ftp import upload_to_ftp  # noqa: F401
 from app.tasks.upload_to_google_drive import upload_to_google_drive  # noqa: F401
+from app.tasks.upload_to_icloud import upload_to_icloud  # noqa: F401
 from app.tasks.upload_to_nextcloud import upload_to_nextcloud  # noqa: F401
 from app.tasks.upload_to_onedrive import upload_to_onedrive  # noqa: F401
 from app.tasks.upload_to_paperless import upload_to_paperless  # noqa: F401