Add editable Timeline Studio video skill 🤖🤖🤖

[MartinDelophy]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• I have read the guidance for submissions involving paid services; this skill does not require a paid service.
• My contribution adds a new skill in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the Agent Skills format.
• I tested project-scope installation with the GitHub Copilot agent target.
• I ran the repository build and verified that docs/README.skills.md is up to date.
• This pull request targets main.

Description

Adds edit-timeline-studio, a portable Agent Skill for creating and refining editable video projects with Timeline Studio.

The skill guides compatible agents through:

• importing explicit local image, video, and audio assets;
• assembling reversible multi-track timelines;
• generating and synchronizing voiceover and captions;
• preserving .timeline as the editable source of truth;
• exporting MP4 or WebM through Timeline Studio's deterministic browser renderer;
• decoding and verifying the resulting video, overlays, captions, dimensions, duration, and audio.

It includes explicit capability boundaries so agents do not claim an edit or deterministic render when browser control, a local checkout, or export verification is unavailable.

Type of Contribution

• New skill file.

Validation

• npm run skill:validate
• npm run build
• git diff --check
• gh skill install ... --from-local --agent github-copilot --scope project

The repository's global eng/fix-line-endings.sh was also invoked. On macOS it reports pre-existing BSD sed incompatibility errors while scanning repository and node_modules files; the two submitted Markdown files were separately confirmed as LF text and pass git diff --check.

Additional Notes

The same skill format is compatible with GitHub Copilot, Codex, Claude Code, and other Agent Skills-compatible hosts. Timeline Studio itself is open source and MIT licensed.

[github-actions]

🔴 Contributor Reputation Check: HIGH risk

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Profile	HIGH
Credential audit	NONE

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[github-actions]

🔒 PR Risk Scan Results

Scanned 2 changed file(s).

Severity	Count
🔴 High	0
🟠 Medium	1
ℹ️ Info	0

Severity	Rule	File	Line	Match
🟠	package-exec-command	docs/README.skills.md	31	| [acreadiness-assess](../skills/acreadiness-assess/SKILL.md)<br />`gh skills install github/awesome-copilot acreadiness-assess` | Run the AgentRC readiness assessment on the curre

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

[github-actions]

🔍 Vally Lint Results

✅ All checks passed

Scope	Checked
Skills	1
Agents	0
Total	1

Severity	Count
❌ Errors	0
⚠️ Warnings	0
ℹ️ Advisories	0

Summary

Level	Finding
ℹ️	npm warn EBADENGINE Unsupported engine {
ℹ️	npm warn EBADENGINE package: 'commander@15.0.0',
ℹ️	npm warn EBADENGINE required: { node: '>=22.12.0' },
ℹ️	npm warn EBADENGINE current: { node: 'v20.20.2', npm: '10.8.2' }
ℹ️	npm warn EBADENGINE }
ℹ️	npm warn deprecated prebuild-install@7.1.3: No longer maintained. Please contact the author of the relevant native addon; alternatives are available.
ℹ️	✅ edit-timeline-studio (2/2 checks passed)
ℹ️	✓ [spec-compliance] All 1 skill(s) are spec-compliant.
ℹ️	✓ spec-compliance: All spec checks passed.
ℹ️	✓ [valid-refs] All file references across 1 skill(s) are valid.

Full linter output

### Linting skills/edit-timeline-studio
npm warn EBADENGINE Unsupported engine {
npm warn EBADENGINE   package: 'commander@15.0.0',
npm warn EBADENGINE   required: { node: '>=22.12.0' },
npm warn EBADENGINE   current: { node: 'v20.20.2', npm: '10.8.2' }
npm warn EBADENGINE }
npm warn deprecated prebuild-install@7.1.3: No longer maintained. Please contact the author of the relevant native addon; alternatives are available.
✅ edit-timeline-studio (2/2 checks passed)
    ✓ [spec-compliance] All 1 skill(s) are spec-compliant.
        ✓ spec-compliance: All spec checks passed.
    ✓ [valid-refs] All file references across 1 skill(s) are valid.
        ✓ valid-refs: All file references resolve to existing files within the skill directory.

1 skill(s) linted, 1 passed