docs(instructions): modernize nextjs-tailwind for Next.js 15+ and Tailwind v4 (#5114) 🤖🤖🤖

[fncreator22]

Summary of Changes

Modernizes instructions/nextjs-tailwind.instructions.md to reflect production standards for Next.js 15+ (App Router) and Tailwind CSS v4, resolving the maintainer staleness audit flagged in #5114.

Key Updates

• Scoped Boundaries: Narrowed applyTo from global '**/*.{ts,tsx,jsx,js,css}' to App Router and component directories ('app/**/*.{ts,tsx,js,jsx}, src/app/**/*.{ts,tsx,js,jsx}, components/**/*.{ts,tsx,js,jsx}') to prevent context pollution in unrelated files.
• Next.js 15+ Async Request APIs: Documented asynchronous access signatures for await params, await searchParams, await cookies(), and await headers().
• Caching Semantics: Clarified default uncached (no-store) fetch and route handler behavior with explicit force-cache and revalidation tag patterns.
• React 19 Server Actions: Modernized form action standards to React 19 useActionState (replacing deprecated useFormState).
• Tailwind CSS v4 CSS-First Configuration: Updated styling guidelines to enforce @import "tailwindcss"; and @theme root CSS configurations instead of legacy tailwind.config.js.
• Documentation Consistency: Regenerated docs/README.instructions.md via npm run build.

Verification & Validation

• npm run build executed successfully; documentation in sync.
• npm run skill:validate passed (435/435 skills valid).
• npm run plugin:validate passed (104/104 plugins and external catalog valid).
• Line endings verified as pure Unix LF (git diff --check clean).
• Soft-gate risk scan (eng/pr-risk-scan.mjs) returned 0 findings.

Resolves part of #5114.

[fncreator22]

@all-contributors add @fncreator22 for doc, content

[github-actions]

🔒 PR Risk Scan Results

Scanned 1 changed file(s).

Severity	Count
🔴 High	0
🟠 Medium	0
ℹ️ Info	0

✅ No matching risk patterns were detected in changed files.

This is an automated soft-gate report. Findings indicate review targets and do not block merge by themselves.

[github-actions]

🚦 Submission status: 👀 Ready for review

Risk tier: merge-risk:medium — New or substantially changed resource without privileged execution
Required to merge: passing submission-gate checks plus 1 approval from reviewers with write access.

Why this tier

• Changes 153 lines (low-risk limit is 40)

Automated checks

Check	Status	Details
Line endings	✅ Passed	Passed · logs
Spelling	✅ Passed	Passed · logs
Generated README consistency	✅ Passed	Passed · logs
Risk scan	✅ Passed	Passed · logs
Contributor reputation	✅ Passed	Passed · logs
Duplicate resource scan	✅ Passed	Passed · logs
PR quality signal	⏭️ Skipped	Skipped by its workflow · logs

Review

• Approvals: 0/1
• Assigned reviewer: not assigned yet — comment /request-review to ask for one
• Review target date: not set
• Still needed: 1 more approval(s)
• No staffed reviewer pool owns these files yet; any reviewer with write access counts as the domain reviewer.

Commands

Command	Who	What it does
/rerun-checks	PR author, maintainers	Re-runs failed or incomplete checks and re-evaluates this gate
/request-review	PR author, maintainers	Asks the review rotation to assign a reviewer (adds needs-reviewer)

_{Updated for 4c36727 · gate run · This comment is maintained automatically — see submission gate docs.}

[github-actions]

🟡 Contributor Reputation Check: MEDIUM risk

Check	Risk
Profile	MEDIUM
Credential audit	NONE

Maintainers: please review this contributor before merging.
See the workflow run for full details.
Automated check powered by AGT.

[fncreator22]

/request-review

[allcontributors]

@fncreator22

I've put up a pull request to add @fncreator22! 🎉

[github-actions]

🙋 Added needs-reviewer. Reviewer routing is assigning a reviewer now.