chore: refactor

[scott-dn]

Why?

refactor and experiment

How?

• using ManualReply
• add approved_at and approved_by
• ledger modular
• token_ids => token_identifiers

Tickets?

• N/A

Contribution checklist?

• [x] The commit messages are detailed
• [x] It does not break existing features (unless required)
• [x] I have performed a self-review of my own code
• [x] Documentation has been updated to reflect the changes
• [x] Tests have been added or updated to reflect the changes
• [x] All code formatting pass
• [x] All lints pass
• [x] All tests pass

Security checklist?

• [x] Injection has been prevented (parameterized queries, no eval or system calls)
• [x] Sensitive data has been identified and is being protected properly

Demo?

Optionally, provide any screenshot, gif or small video.