mmn#510: migrate json to binary protobuf use vtprotobuf

[hieudinhngoc-ncc]

Ticket

#510

General

• No unnecessary files, debug logs, or commented code included.
• PR has at least 1 peer approval before senior review.
• I fully understand the code I submitted.
• No hardcoded configuration or secrets.
• Environment Variables changes? (Leave unchecked if N/A)

Design & Solution Clarity

• This is refactor task

Design link (diagram / doc):

• This is refactor task

Testing

• Result test in the ticket

Note: Complex logic must not rely on manual testing only.

Peer Review Checklist

• I understand the overall solution and flow.
• The code follows the provided design diagram.
• No obvious logic or security issues found.
• Tests are sufficient for the scope of this change.

[hoangdohuy]

LGTM