ci: add automated skill review for SKILL.md pull requests

[popey]

Hullo! Thanks for merging the skill improvements earlier. This is a follow-up that adds a lightweight GitHub Action to automatically review any SKILL.md files when they're changed in a PR, using tessl skill review.

• Triggers only on PRs that touch **/SKILL.md
• Posts review results as a PR comment
• Minimal permissions: pull-requests: write and contents: read

This way you and your contributors get an instant quality signal on skill changes before manual review — no signup or tokens needed.

[Jeffallan]

@popey Thanks for the PR. One question before we review further: the action installs the tessl CLI via curl -fsSL https://get.tessl.io | sh (in src/install-tessl.ts), but tessl is available on npm as a pinnable package. Is there a reason the action uses curl | sh instead of npx tessl or npm install -g tessl@0.73.0?

[popey]

Hi @Jeffallan, apologies for the slow reply! Good question — the tesslio/skill-review action has since been updated to use a dedicated tesslio/setup-tessl action for the installation step, which makes the install process more transparent and auditable. Happy to answer any other questions.