feat(core): move context docs to user prompt (#10162)

Fix issue [BS-2522](https://linear.app/affine-design/issue/BS-2522).

### Why make this change?
If the user data contains illegal content, carrying the user data in the system prompt will run the risk of having the account banned.

### What Changed?
- Move the `Context Documents` to the user prompt.
- Add `withPrompt` in `QueryChatHistoriesInput` options.
- Get chat histories without prompt messages.
- Omit document context when saving messages to the `aiSessionMessage` db.

packages/frontend/graphql/src/schema.ts

@@ -1298,6 +1298,7 @@ export interface QueryChatHistoriesInput {
   sessionId?: InputMaybe<Scalars['String']['input']>;
   sessionOrder?: InputMaybe<ChatHistoryOrder>;
   skip?: InputMaybe<Scalars['Int']['input']>;
+  withPrompt?: InputMaybe<Scalars['Boolean']['input']>;
 }
 
 export interface QueryTooLongDataType {