feat: add ambiguous external write recovery skill 🤖🤖🤖

[artiehinz]

Summary

Adds one vendor-neutral skill for a risky edge case: an external write may finish even when its response is lost. The skill tells agents to record the attempt, treat the result as uncertain, check destination state, and retry only after proving the write did not happen or confirming provider idempotency.

Scope

• One new SKILL.md
• One generated skills-index entry
• No remote service, dependency, plugin, or runtime code
• Shared checkpoints exclude credentials, personal data, and destination payloads

Validation

• npm run skill:validate: all 394 skills valid
• npm run build: index and marketplace generation passed

[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]

🔍 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	✅ recover-ambiguous-external-writes (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.
ℹ️	✓ valid-refs: All file references resolve to existing files within the skill directory.
ℹ️	1 skill(s) linted, 1 passed

Full linter output

### Linting skills/recover-ambiguous-external-writes
✅ recover-ambiguous-external-writes (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

[github-actions]

🔴 Contributor Reputation Check: HIGH risk

Check	Risk
Profile	HIGH
Credential audit	NONE

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