fix(tls): handle bracketed IPv6 hostnames in checkServerIdentity

[Abioy]

Strip IPv6 literal brackets before net.isIP() check, since net.isIP("[::1]") returns 0. The brackets are a URL convention, not part of the actual address, so they must be removed before IP validation and matching.

What does this PR do?

Fixes tls.checkServerIdentity rejecting valid IPv6 hostnames in bracket form like [::1] or [2001:db8::1]. The brackets are a URL convention for IPv6 literals, not part of the actual IP address. Previously, net.isIP("[::1]") returned 0 (not an IP), causing the function to incorrectly treat it as a DNS name and always fail validation.

How did you verified your code works?

• Stripped-bracket hostnames now pass net.isIP() correctly: [::1] → ::1 → isIP=6
• All 42 existing test cases in test-tls-check-server-identity.js continue to pass
• Added 6 new IPv6 test cases covering: bare ::1, bracketed [::1], uppercase [2001:DB8::1], mismatched addresses, and bracketed IP against DNS-only SAN

[claude]

Claude Code Review

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between b8ecc78 and 15b0b3f.

📒 Files selected for processing (2)

• src/js/node/tls.ts
• test/js/node/test/parallel/test-tls-check-server-identity.js

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Walkthrough

This PR fixes IPv6 server identity validation in Node.js TLS by stripping bracket literals ([ and ]) from IPv6 hostnames before IP validation, ensuring they are correctly matched against certificate IP SANs. New test cases validate IPv6 handling across direct and bracketed formats, matching and mismatching scenarios.

Changes

IPv6 Server Identity Validation

Layer / File(s)	Summary
IPv6 literal handling with bracket stripping src/js/node/tls.ts, test/js/node/test/parallel/test-tls-check-server-identity.js	checkServerIdentity now strips leading and trailing brackets from IPv6 hostnames before calling net.isIP and comparing against certificate IP SANs. Test vectors cover unbracketed and bracketed IPv6 formats, correct IP matching, mismatched SAN failures, and DNS-only SAN error paths.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: fixing TLS checkServerIdentity to handle bracketed IPv6 hostnames, which is the core purpose of this pull request.
Description check	✅ Passed	The description includes both required template sections ('What does this PR do?' and 'How did you verify your code works?') with detailed, substantive content addressing the fix, its rationale, and comprehensive test verification.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[Abioy]

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