refactor(api): improve memory service dependency injection and code organization

- Update ShortService and LongService constructors to accept db Session parameter for proper dependency injection instead of using module-level db instance
- Reorganize imports in memory_short_term_controller.py following PEP 8 conventions (stdlib, third-party, local imports)
- Add comprehensive docstrings with type hints to ShortService and LongService methods for better code documentation
- Fix import organization in memory_short_service.py to group related imports and improve readability
- Reorganize imports in user_memory_service.py to follow consistent import ordering patterns
- Update ShortService instantiation in analytics_memory_types to pass db parameter
- Remove module-level db instance initialization in favor of caller-managed database session lifecycle
- Add type annotations to method signatures (end_user_id: str, db: Session, return types)
- Improve code formatting and spacing consistency across memory service files

api/app/services/memory_short_service.py

@@ -1,22 +1,37 @@
+from typing import Dict, List
+
+from sqlalchemy.orm import Session
 
 from app.core.logging_config import get_api_logger
-from app.db import get_db
-from app.repositories.memory_short_repository import LongTermMemoryRepository
-from app.repositories.memory_short_repository import ShortTermMemoryRepository
-
+from app.repositories.memory_short_repository import (
+    LongTermMemoryRepository,
+    ShortTermMemoryRepository,
+)
 
 api_logger = get_api_logger()
-db=next(get_db())
+
+
 class ShortService:
-    def __init__(self, end_user_id):
+    def __init__(self, end_user_id: str, db: Session) -> None:
+        """Service for short-term memory queries.
+
+        Args:
+            end_user_id: The end user identifier to query memories for.
+            db: SQLAlchemy database session (caller-managed lifecycle).
+        """
         self.short_repo = ShortTermMemoryRepository(db)
         self.end_user_id = end_user_id
 
-    def get_short_databasets(self):
+    def get_short_databasets(self) -> List[Dict]:
+        """Retrieve the latest short-term memory entries for the user.
+
+        Returns:
+            List[Dict]: List of memory dicts with retrieval, message, and answer keys.
+        """
         short_memories = self.short_repo.get_latest_by_user_id(self.end_user_id, 3)
         short_result = []
         for memory in short_memories:
-            deep_expanded = {}  # Create a new dictionary for each memory
+            deep_expanded = {}
             messages = memory.messages
             aimessages = memory.aimessages
             retrieved_content = memory.retrieved_content or []
@@ -27,23 +42,41 @@ class ShortService:
             for item in retrieved_content:
                 if isinstance(item, dict):
                     for key, values in item.items():
-                        retrieval_source.append({"query": key, "retrieval": values,"source":"上下文记忆"})
+                        retrieval_source.append({"query": key, "retrieval": values, "source": "上下文记忆"})
 
             deep_expanded['retrieval'] = retrieval_source
-            deep_expanded['message'] = messages  # 修正拼写错误
+            deep_expanded['message'] = messages
             deep_expanded['answer'] = aimessages
             short_result.append(deep_expanded)
         return short_result
-    def get_short_count(self):
+
+    def get_short_count(self) -> int:
+        """Count total short-term memory entries for the user.
+
+        Returns:
+            int: Number of short-term memory records.
+        """
         short_count = self.short_repo.count_by_user_id(self.end_user_id)
         return short_count
 
+
 class LongService:
-    def __init__(self, end_user_id):
+    def __init__(self, end_user_id: str, db: Session) -> None:
+        """Service for long-term memory queries.
+
+        Args:
+            end_user_id: The end user identifier to query memories for.
+            db: SQLAlchemy database session (caller-managed lifecycle).
+        """
         self.long_repo = LongTermMemoryRepository(db)
         self.end_user_id = end_user_id
-    def get_long_databasets(self):
-        # 获取长期记忆数据
+
+    def get_long_databasets(self) -> List[Dict]:
+        """Retrieve long-term memory retrieval data for the user.
+
+        Returns:
+            List[Dict]: List of dicts with query and retrieval keys.
+        """
         long_memories = self.long_repo.get_by_user_id(self.end_user_id, 1)
 
         long_result = []