chore: normalize skills-ref frontmatter

[dallascrilley]

Normalize SKILL frontmatter to pass the official skills-ref validator.\n\n- remove unsupported top-level fields from frontmatter\n- preserve metadata within supported fields\n- keep skill behavior unchanged\n\nValidation:\n- skills-ref validate .\n- skills-ref validate variants/open\n

[dallascrilley]

Validation summary:\n- ✅\n- Valid skill: variants/open ✅\n\nScope is intentionally limited to frontmatter normalization for compatibility. Skill behavior and body instructions are unchanged.

[dallascrilley]

Validation summary:

• skills-ref validate skills/last30days ✅
• skills-ref validate skills/last30days/variants/open ✅

Scope is intentionally limited to frontmatter normalization for skills-ref compatibility. Skill behavior and body instructions are unchanged.

[mvanhorn]

Thanks for the contribution, but I need to request changes here — this PR removes fields that are required for the skill to function in Claude Code:

• user-invocable: true — without this, the skill doesn't appear as a slash command
• allowed-tools — defines the security boundary for what tools the skill can use
• argument-hint — provides usage examples in the CLI
• version — required for the plugin distribution system (current main is at 2.9.5, this branch has 2.8)
• The metadata block — contains dependency declarations and discovery tags

The variant rename from name: last30days to name: "open" would also break variant detection.

Could you share what "skills-ref validator" flagged these fields? Claude Code's skill spec supports all of them. If there's a specific validator with different requirements, I'd like to understand the gap — but removing these fields would break the skill entirely.

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Review assisted by Claude Code

[mvanhorn]

Hey, sorry for the delay on this one - it's been a wild couple of weeks. We hit #1 trending on GitHub and the flood of activity has been hard to keep up with. The frontmatter normalization is clean and the validation summary is helpful. I'm holding off on all merges until the v3.0 refactor lands since it changes the skill file structure, but I promise I'll consider this once things settle. Appreciate the quality contribution.