chore: clean up go mod & fix mail link

[GuangmingLuo]

Change-Id: I408a58e2cab97478fcba9abf1277a965fd0bffba

What type of PR is this?

chore

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en:

1. clean up go mod, separate direct and indirect dependency
2. upgrade hertz and gopkg version to latest
3. fix mail link in readme

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[Copilot]

Pull Request Overview

This PR performs maintenance tasks on the Go module dependencies and fixes documentation links. It reorganizes the go.mod file to separate direct and indirect dependencies, upgrades key dependencies to their latest versions, and corrects email links in README files.

• Clean up go.mod structure by consolidating require blocks and properly organizing direct vs indirect dependencies
• Upgrade hertz framework from v0.10.0 to v0.10.2 and gopkg from v0.1.1 to v0.1.3
• Fix email links in README files by adding proper mailto: protocol

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
backend/go.mod	Restructured dependency organization and upgraded key packages
README.zh_CN.md	Fixed email link by adding mailto: protocol
README.md	Fixed email link by adding mailto: protocol

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
see 7 files with indirect coverage changes

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