feat(solaris): migrate to pydantic ai, wired respond agent through di providers

src/utils/db/models/session.py

@@ -1,14 +1,15 @@
 from typing import Annotated, List
 
 from beanie import Document, Indexed
-from google.genai.types import Content
 from pydantic import BaseModel, Field
+from pydantic_ai.messages import ModelMessage
 
 
 class SessionBase(BaseModel):
     chat_id: Annotated[int, Indexed(unique=True)]
-    system_prompt: str
-    history: List[Content] = Field(default_factory=list)
+    system_prompt_override: str = None
+    history: List[ModelMessage] = Field(default_factory=list)
+    api_key_override: str = None
 
 
 class __CommonSessionRepository(SessionBase, Document):
@@ -17,10 +18,17 @@ class __CommonSessionRepository(SessionBase, Document):
         return await cls.find_one(cls.chat_id == chat_id)
 
     @classmethod
-    async def create_empty(cls, chat_id: int, system_prompt: str):
-        return await cls(chat_id=chat_id, system_prompt=system_prompt).insert()
+    async def create_empty(cls, chat_id: int):
+        return await cls(chat_id=chat_id).insert()
 
-    async def update_history(self, history: List[Content]):
+    @classmethod
+    async def get_or_create_by_chat_id(cls, chat_id: int):
+        session = await cls.get_by_chat_id(chat_id)
+        if not session:
+            session = await cls.create_empty(chat_id=chat_id)
+        return session
+
+    async def update_history(self, history: List[ModelMessage]):
         await self.set({self.history: history})