refactor: imports and reorganize domain structure

- Updated import statements across multiple modules to use relative imports for better encapsulation.
- Consolidated and organized the `__init__.py` files in various domain packages to expose necessary classes and functions.
- Improved code readability and maintainability by grouping related imports and removing unused ones.
- Ensured consistent import patterns across the domain, enhancing the overall structure of the codebase.

domain/processors/builtin/vector_index.py

@@ -8,12 +8,14 @@ from fastapi.responses import Response
 from PIL import Image
 
 from ..base import BaseProcessor
-from domain.ai.inference import describe_image_base64, get_text_embedding, provider_service
-from domain.ai.service import (
-    VectorDBService,
+from domain.ai import (
     DEFAULT_VECTOR_DIMENSION,
-    VECTOR_COLLECTION_NAME,
     FILE_COLLECTION_NAME,
+    VECTOR_COLLECTION_NAME,
+    VectorDBService,
+    describe_image_base64,
+    get_text_embedding,
+    provider_service,
 )