Modernize dm (excluding dm/pkg)

[dveeden]

What problem does this PR solve?

Issue Number: ref #12691

What is changed and how it works?

Check List

Tests

• Manual test (add detailed scripts or steps below)

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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Details

Needs approval from an approver in each of these files:

• cmd/dm-worker/OWNERS
• dm/OWNERS
• dm/config/OWNERS

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[gemini-code-assist]

Code Review

This pull request modernizes the codebase by adopting Go 1.21 and 1.22 features, such as replacing interface{} with any, using for range over integers, utilizing maps.Copy and slices.Contains, and leveraging fmt.Appendf. However, a critical issue was identified across multiple files where standard sync.WaitGroup usages were incorrectly refactored to use a non-existent Go method (e.g., wg.Go(func() { ... })). This will result in compilation failures, and these changes must be reverted to the standard wg.Add(1) and go func() pattern.

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[dveeden]

/cc @kennytm @GMHDBJD