refactor: simplify sync to parallel entity sync with cursor pagination

- All entities (facts, todos, daily, conversations) sync in parallel
- Daily uses same cursor-based sync as other entities (removed duplicate recent-days logic)
- Conversations sync to separate folder grouped by days
- Utterances sorted by time then id, without timestamps
- Removed --recent-days flag

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ex3ndr