fix(session): order prompt loop by message creation

[rekram1-node]

Summary

• order session message pagination by database creation time and row sequence instead of message IDs
• use database-created time for prompt loop latest-message comparisons
• add regression coverage for non-chronological message IDs

Tests

• bun test test/session/messages-pagination.test.ts
• bun test test/session/message-v2.test.ts
• bun test test/session/prompt.test.ts
• bun typecheck