refactor(tarko): optimize agent-server-next dao level

[cjraft]

Summary

1. Merge the src/storage and src/dao directory codes
2. Delete redundant code and unify the db layer operation in DAO (Data Access Object)

Checklist

• Added or updated necessary tests (Optional).
• Updated documentation to align with changes (Optional).
• Verified no breaking changes, or prepared solutions for any occurring breaking changes (Optional).
• My change does not involve the above items.

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