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/ai/__init__.py

@@ -1,28 +1,61 @@
-from .api import router_ai, router_vector_db
+from .inference import (
+    MissingModelError,
+    chat_completion,
+    chat_completion_stream,
+    describe_image_base64,
+    get_text_embedding,
+    provider_service,
+    rerank_texts,
+)
 from .service import (
     AIProviderService,
+    FILE_COLLECTION_NAME,
+    VECTOR_COLLECTION_NAME,
+    DEFAULT_VECTOR_DIMENSION,
     VectorDBConfigManager,
     VectorDBService,
-    DEFAULT_VECTOR_DIMENSION,
-    ABILITIES,
-    normalize_capabilities,
 )
 from .types import (
+    ABILITIES,
     AIDefaultsUpdate,
     AIModelCreate,
     AIModelUpdate,
     AIProviderCreate,
     AIProviderUpdate,
     VectorDBConfigPayload,
+    normalize_capabilities,
+)
+from .vector_providers import (
+    BaseVectorProvider,
+    MilvusLiteProvider,
+    MilvusServerProvider,
+    QdrantProvider,
+    get_provider_class,
+    get_provider_entry,
+    list_providers,
 )
 
 __all__ = [
-    "router_ai",
-    "router_vector_db",
+    "MissingModelError",
+    "chat_completion",
+    "chat_completion_stream",
+    "describe_image_base64",
+    "get_text_embedding",
+    "provider_service",
+    "rerank_texts",
     "AIProviderService",
     "VectorDBService",
     "VectorDBConfigManager",
     "DEFAULT_VECTOR_DIMENSION",
+    "VECTOR_COLLECTION_NAME",
+    "FILE_COLLECTION_NAME",
+    "BaseVectorProvider",
+    "MilvusLiteProvider",
+    "MilvusServerProvider",
+    "QdrantProvider",
+    "list_providers",
+    "get_provider_entry",
+    "get_provider_class",
     "ABILITIES",
     "normalize_capabilities",
     "AIDefaultsUpdate",