build(scripts): adopt PowerShell 7.4 floor repo-wide

[WilliamBerryiii]

Pull Request

Description

Adopts PowerShell 7.4 as the repo-wide floor, in two parts:

1. Analyzer target — scripts/linting/PSScriptAnalyzer.psd1 sets PSUseCompatibleSyntax.TargetVersions to @('7.4'), dropping the out-of-support 5.1 / 7.0 / 7.2 targets. This config is the single source of truth applied to all PowerShell files.
2. Runtime floor — bumps #Requires -Version 7.0 to 7.4 across 91 source scripts and modules under scripts/, .github/skills/, and .github/hooks/. The PowerShell convention (powershell.instructions.md), docs/contributing/copyright-headers.md, and scripts/collections/README.md are aligned to 7.4, and plugins/ generated outputs were regenerated via npm run plugin:generate.

Rebased onto main (previously stacked on feat/1637-d-skill-paths). The original "bootstrap python test deps" change was dropped: main's Invoke-PythonTests.ps1 already runs uv sync before pytest, and the polyglot fuzz harnesses run under pytest without atheris, so syncing the manylinux-only fuzz group is unnecessary and would break test:py on macOS/Windows.

Note: skill scripts distributed via collections now require PowerShell 7.4+ at runtime. This matches the repo's supported toolchain (devcontainer powershell:1 feature and GitHub Actions both ship 7.4+).

Related Issue(s)

Closes #1827

Type of Change

Select all that apply:

Code & Documentation:

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to change)
• Documentation update

Infrastructure & Configuration:

• GitHub Actions workflow
• Linting configuration (markdown, PowerShell, etc.)
• Security configuration
• DevContainer configuration
• Dependency update

AI Artifacts:

• Reviewed contribution with prompt-builder agent and addressed all feedback
• Copilot instructions (.github/instructions/*.instructions.md)
• Copilot prompt (.github/prompts/*.prompt.md)
• Copilot agent (.github/agents/*.agent.md)
• Copilot skill (.github/skills/*/SKILL.md)

Other:

• Script/automation (.ps1, .sh, .py)
• Other (please describe):

Testing

• npm run lint:ps — all PowerShell files pass with the 7.4 syntax target.
• npm run lint:md — 0 errors on edited docs.
• npm run test:ps -- -TestPath scripts/tests/linting/Test-CopyrightHeaders.Tests.ps1 — 55/55 passed (copyright-header fixtures updated to 7.4).
• npm run plugin:generate — regenerated plugins/ so generated #Requires copies match.

Checklist

Required Checks

• Documentation is updated (if applicable)
• Files follow existing naming conventions
• Changes are backwards compatible (if applicable)
• Tests added for new functionality (if applicable)

Required Automated Checks

• Markdown linting: npm run lint:md
• Frontmatter validation: npm run lint:frontmatter
• PowerShell analysis: npm run lint:ps
• Plugin freshness: npm run plugin:generate

Security Considerations

• This PR does not contain any sensitive or NDA information
• Any new dependencies have been reviewed for security issues
• Security-related scripts follow the principle of least privilege

Additional Notes

Raising the runtime floor is a deliberate breaking change: scripts now refuse to run on PowerShell 7.0–7.3. This aligns the runtime contract with the analyzer target and the repo's supported toolchain.

The base branch was changed.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.00%. Comparing base (61d1b5f) to head (aeabac8).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1842      +/-   ##
==========================================
+ Coverage   81.64%   87.00%   +5.36%     
==========================================
  Files         130       79      -51     
  Lines       19470     9022   -10448     
  Branches       12       12              
==========================================
- Hits        15897     7850    -8047     
+ Misses       3570     1169    -2401     
  Partials        3        3              

Flag	Coverage Δ
docusaurus	61.84% <ø> (ø)
pester	86.02% <ø> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...erimental/powerpoint/scripts/Invoke-EmbedAudio.ps1	78.78% <ø> (ø)
...perimental/powerpoint/scripts/Invoke-ExportSvg.ps1	78.78% <ø> (ø)
...ental/powerpoint/scripts/Invoke-GenerateThemes.ps1	76.66% <ø> (ø)
...imental/powerpoint/scripts/Invoke-PptxPipeline.ps1	79.26% <ø> (ø)
...mental/tts-voiceover/scripts/Invoke-EmbedAudio.ps1	0.00% <ø> (ø)
...tts-voiceover/scripts/Invoke-GenerateVoiceover.ps1	0.00% <ø> (ø)
...voiceover/scripts/Modules/TtsVoiceoverHelpers.psm1	93.75% <ø> (ø)
...h-code-scanning/scripts/Get-CodeScanningAlerts.ps1	97.50% <ø> (ø)
...ub/skills/shared/pr-reference/scripts/generate.ps1	95.07% <ø> (-0.71%)	⬇️
...shared/pr-reference/scripts/list-changed-files.ps1	94.02% <ø> (ø)
... and 40 more

... and 53 files with indirect coverage changes

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[github-actions]

Eval Execution

✅ Status: Passed — no merge-blocking failures (8 advisory assertion failure(s) present)

• Artifacts evaluated: 1
• Specs run: 1
• Assertions passed: 7
• Assertions failed (blocking): 0
• Assertions failed (advisory): 8
• Failed specs (merge-blocking): 0

Artifact	Kind	Status	Specs	Passed	Failed (blocking)	Failed (advisory)
powershell	instruction	⚠️ advisory-fail	1	7	0	8

Legend — ✅ clean · ⚠️ advisory failures only (non-blocking) · ⏭️ skipped · ❌ merge-blocking failure

Only Failed specs (merge-blocking) gates this PR. Advisory assertion failures are signal-quality checks captured during iteration; review them, but they do not block merge and may be acceptable.