Add vardoger-analyze skill

[dstrupl]

Summary

Adds a new skill, vardoger-analyze, that tells Copilot how to drive the local vardoger CLI to personalize the GitHub Copilot CLI assistant from the user's own conversation history.

vardoger is a local-first tool (Apache-2.0, published on PyPI) that reads ~/.copilot/history-session-state/, extracts recurring preferences and conventions, and writes a fenced personalization block into ~/.copilot/copilot-instructions.md. The block is idempotent (<!-- vardoger:start --> ... <!-- vardoger:end -->), so hand-authored instructions in the same file are preserved. No network calls, no uploads — everything runs on the user's machine.

The skill:

• Verifies the vardoger CLI is on PATH and prints install guidance (pipx install vardoger) if not.
• Walks the assistant through the prepare → summarize → synthesize → write loop.
• Uses only the real vardoger CLI surface (status --platform copilot --json, prepare --platform copilot [--batch N | --synthesize], write --platform copilot --scope global). Each command is verified against vardoger 0.2.1.

Validation

$ npm run skill:validate
Validating vardoger-analyze...
✅ vardoger-analyze is valid
…
✅ All 309 skills are valid
🎉 Skill validation passed

Checklist

• New skill lives at skills/vardoger-analyze/SKILL.md.
• Folder name matches name in frontmatter.
• description includes explicit trigger phrases.
• npm run skill:validate passes locally against HEAD.
• No bundled assets (skill is a single SKILL.md).
• Apache-2.0 licensed; not a plugin from a remote source (this is a self-contained skill, no remote plugin reference).

Links

• Project: https://github.com/dstrupl/vardoger
• License: Apache-2.0
• Privacy policy: https://github.com/dstrupl/vardoger/blob/main/PRIVACY.md
• PyPI: https://pypi.org/project/vardoger/ (current version 0.2.1)

[github-actions]

⚠️ This PR targets main, but PRs should target staged.

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Please close this PR and re-open it against the staged branch.

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or run: gh pr edit 1461 --base staged