Improve code quality per PR #11 and #12 review feedback

- Improve CORS config readability by breaking nested os.getenv() into
  explicit fallback steps (_default_cors_origin -> _cors_origins_str)
- Remove duplicate import os statement
- Consolidate all Celery task imports at module level
- Remove inline imports from function bodies

surfsense_backend/app/config/__init__.py

@@ -138,7 +138,8 @@ class Config:
     # CORS Configuration
     # Comma-separated list of allowed origins, defaults to frontend URL
     # Note: Wildcard "*" is not allowed when allow_credentials=True
-    _cors_origins_str = os.getenv("CORS_ORIGINS", os.getenv("NEXT_FRONTEND_URL", "http://localhost:3000"))
+    _default_cors_origin = os.getenv("NEXT_FRONTEND_URL", "http://localhost:3000")
+    _cors_origins_str = os.getenv("CORS_ORIGINS", _default_cors_origin)
     CORS_ORIGINS = [origin.strip() for origin in _cors_origins_str.split(",") if origin.strip()]
 
     # Google OAuth

surfsense_backend/app/routes/documents_routes.py

@@ -26,7 +26,12 @@ from app.schemas import (
 )
 from app.users import current_active_user
 from app.utils.check_ownership import check_ownership
-from app.tasks.celery_tasks.document_tasks import process_file_upload_task
+from app.tasks.celery_tasks.document_tasks import (
+    process_crawled_url_task,
+    process_extension_document_task,
+    process_file_upload_task,
+    process_youtube_video_task,
+)
 
 try:
     asyncio.set_event_loop_policy(asyncio.DefaultEventLoopPolicy())
@@ -34,8 +39,6 @@ except RuntimeError as e:
     print("Error setting event loop policy", e)
     pass
 
-import os
-
 os.environ["UNSTRUCTURED_HAS_PATCHED_LOOP"] = "1"
 
 
@@ -53,10 +56,6 @@ async def create_documents(
         await check_ownership(session, SearchSpace, request.search_space_id, user)
 
         if request.document_type == DocumentType.EXTENSION:
-            from app.tasks.celery_tasks.document_tasks import (
-                process_extension_document_task,
-            )
-
             for individual_document in request.content:
                 # Convert document to dict for Celery serialization
                 document_dict = {
@@ -70,14 +69,11 @@ async def create_documents(
                     document_dict, request.search_space_id, str(user.id)
                 )
         elif request.document_type == DocumentType.CRAWLED_URL:
-            from app.tasks.celery_tasks.document_tasks import process_crawled_url_task
-
             for url in request.content:
                 process_crawled_url_task.delay(
                     url, request.search_space_id, str(user.id)
                 )
         elif request.document_type == DocumentType.YOUTUBE_VIDEO:
-            from app.tasks.celery_tasks.document_tasks import process_youtube_video_task
 
             for url in request.content:
                 process_youtube_video_task.delay(