* fix_: chats and message history loading after login takes too much time
* chore_: split to small functions to writing unit test easily
* test_: add test
* chore_: improve OldestMessageWhisperTimestampByChatIDs function
- Use 'any' type instead of 'interface{}' for args slice
- Add error check after rows iteration
* chore_: optimize OldestMessageWhisperTimestampByChatIDs query
This commit simplifies and optimizes the SQL query in the OldestMessageWhisperTimestampByChatIDs function. The changes include:
1. Removing the subquery and ROW_NUMBER() function
2. Using MIN() and GROUP BY instead of the previous approach
3. Directly selecting the required columns in a single query
These changes should improve the performance of the function, especially for large datasets, while maintaining the same functionality.