chore(nextjs): Update middleware check for proxy usage (#7269)

[alexcarpenter]

Description

Backports #7269

Checklist

• pnpm test runs as expected.
• pnpm build runs as expected.
• (If applicable) JSDoc comments have been added or updated for any package exports
• (If applicable) Documentation has been updated

Type of change

• 🐛 Bug fix
• 🌟 New feature
• 🔨 Breaking change
• 📖 Refactoring / dependency upgrade / documentation
• other:

Summary by CodeRabbit

• New Features

  • Version-aware Next.js detection to tailor middleware guidance and wording.

• Bug Fixes

  • Improved middleware location checks and user-facing messages, including proxy wording for Next.js 16+.
  • Updated auth-related guidance to reflect detected Next.js version.

• Tests

  • Added tests covering Next.js version detection and conditional messaging across versions.

• Chores

  • Added a changeset entry.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 6ea99af

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 0 packages

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Project	Deployment	Actions	Updated (UTC)
clerk-js-sandbox	Ready	Preview, Comment	Jan 29, 2026 10:12pm

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commit: 6ea99af

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds Next.js version detection and a new sdk-versions module exposing isNext13, isNextWithUnstableServerActions, isNext16OrHigher, and middlewareFileReference. Refactors middleware location checks and error messages to account for proxy.(ts|js) in Next.js 16+ while preserving prior middleware behavior for earlier versions. Updates auth error helpers to accept a parameterized file reference. Tests updated to detect Next.js major version and assert version-appropriate messages; new unit tests cover sdk-versions logic.

Possibly related PRs

Related changes add proxy.(ts|js) support alongside middleware.(ts|js) for Next.js 16+.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: updating the Next.js middleware check to support proxy usage, which aligns with the changeset additions of proxy file detection logic.

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Warning

Review ran into problems

🔥 Problems

Errors were encountered while retrieving linked issues.

Errors (1)

• PR-7269: Entity not found: Issue - Could not find referenced Issue.

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