*: upgrade go version to v1.25.6 to avoid security vulnerabilities

[djshow832]

What problem does this PR solve?

Issue Number: close #1078

Problem Summary:

Target: `usr/bin/tiproxy` (gobinary) (7 vulnerabilities)
[MEDIUM] Risk Library:  golang.org/x/crypto  Installed: `v0.40.0`
[CVE-2025-47914](https://nvd.nist.gov/vuln/detail/CVE-2025-47914) - MEDIUM - Fixed: `0.45.0`
[CVE-2025-58181](https://nvd.nist.gov/vuln/detail/CVE-2025-58181) - MEDIUM - Fixed: `0.45.0`
[UNKNOWN] Risk Library:  stdlib  Installed: `v1.25.5`
[CVE-2025-61726](https://nvd.nist.gov/vuln/detail/CVE-2025-61726) - UNKNOWN - Fixed: `1.24.12, 1.25.6`
[CVE-2025-61728](https://nvd.nist.gov/vuln/detail/CVE-2025-61728) - UNKNOWN - Fixed: `1.24.12, 1.25.6`
[CVE-2025-61730](https://nvd.nist.gov/vuln/detail/CVE-2025-61730) - UNKNOWN - Fixed: `1.24.12, 1.25.6`

Target: `usr/bin/tiproxyctl` (gobinary) (3 vulnerabilities)
[UNKNOWN] Risk Library:  stdlib  Installed: `v1.25.5`
[CVE-2025-61726](https://nvd.nist.gov/vuln/detail/CVE-2025-61726) - UNKNOWN - Fixed: `1.24.12, 1.25.6`
[CVE-2025-61728](https://nvd.nist.gov/vuln/detail/CVE-2025-61728) - UNKNOWN - Fixed: `1.24.12, 1.25.6`
[CVE-2025-61730](https://nvd.nist.gov/vuln/detail/CVE-2025-61730) - UNKNOWN - Fixed: `1.24.12, 1.25.6`

What is changed and how it works:

• Upgrade go to v1.25.6
• Upgrade golang.org/x/crypto to latest
• Use go1.25.6 to compile golangci-lint

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Notable changes

• Has configuration change
• Has HTTP API interfaces change
• Has tiproxyctl change
• Other user behavior changes

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[djshow832]

/retest

[djshow832]

/retest

[djshow832]

/retest

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (main@f52d4a5). Learn more about missing BASE report.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1080   +/-   ##
=======================================
  Coverage        ?   66.73%           
=======================================
  Files           ?      141           
  Lines           ?    14630           
  Branches        ?        0           
=======================================
  Hits            ?     9764           
  Misses          ?     4193           
  Partials        ?      673           

Flag	Coverage Δ
unit	66.73% <ø> (?)

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: YangKeao

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Details

Needs approval from an approver in each of these files:

• OWNERS [YangKeao]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-02-09 02:21:05.746085241 +0000 UTC m=+151481.440225091: ☑️ agreed by YangKeao.

[djshow832]

/cherry-pick release-nextgen-20251023

[ti-chi-bot]

@djshow832: new pull request created to branch release-nextgen-20251023: #1082.

Details

In response to this:

/cherry-pick release-nextgen-20251023

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[djshow832]

/cherry-pick release-1.3

[ti-chi-bot]

@djshow832: new pull request created to branch release-1.3: #1083.
But this PR has conflicts, please resolve them!

Details

In response to this:

/cherry-pick release-1.3

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.