[Feature] Add how to ensure skills are up to date

[riggaroo]

Current README.md doesn't detail how to ensure the skills you have downloaded are up-to-date. Can you include this information?

[hamen]

Hit this same question on my own multi-skill repo and landed on a layered approach, sharing becase why not 😀

Three sources of version truth, kept in sync:

1. SKILL.md frontmatter -> metadata.version: "2.0.1" (semver). What aninspecting agent or human sees when reading the skill.
2. .claude-plugin/plugin.json -> "version": "2.0.1". What Claude Code reads to detect updates via /plugin update.
3. README top line + dated changelog at the bottom. What lets a user on 1.5.0 decide whether 2.0.1 matters without crawling git log.

If those three drift, users can't tell what's current.

Semver applies to distribution, not just content. When I had to restructure for https://agentskills.io/specification compliance, the install URL changed and anyone on the old URL silently stopped receiving updates. I cut a 2.0.0 just for that and documented the required reinstall step in the README. Rubric/content changes inside the skill don't usually warrant a major bump; install-path changes do.

Update mechanics by harness, worth spelling out in the README:

• Claude Code: /plugin update — but only works if .claude-plugin/plugin.json exists with a bumped version.
• Cursor: re-import from team marketplace.
• Symlinked manual install: git pull in the repo.

For this repo specifically, the existing skills (e.g. jetpack-compose/migration/migrate-xml-views-to-jetpack-compose/SKILL.md) carry no metadata.version and there's no root .claude-plugin/marketplace.json, so neither harness can detect updates programmatically today.

Adding both would unlock /plugin update for users.