ci: verify generated agent/skill files stay in sync with their sources

[YAMRAJ13y]

Problem

AGENTS.md documents a required workflow:

• After editing AGENTS.md, run bash scripts/sync-agent-rules.sh to regenerate platform-specific instruction files.
• After editing .claude/skills/clone-website/SKILL.md, run node scripts/sync-skills.mjs to regenerate the skill for all platforms.

But nothing enforces it. A contributor can edit a source file and forget to regenerate, silently drifting the 13 committed generated files (Cursor, Windsurf, Gemini, Codex, Copilot, Amazon Q, Continue, Cline, OpenCode, Augment) from their AGENTS.md / SKILL.md sources. The current CI only runs lint / typecheck / build, so this drift ships unnoticed.

Fix

Adds a sync job to the CI workflow that:

1. Re-runs the two existing sync scripts.
2. Fails the build with a clear remediation message (and a git diff --stat) if the working tree is now dirty — i.e. the committed generated files don't match their sources.

::error::Generated files are out of sync with their sources (AGENTS.md / SKILL.md).
Run the sync scripts locally and commit the result:
  bash scripts/sync-agent-rules.sh
  node scripts/sync-skills.mjs

Notes

• Mirrors the documented workflow exactly; no behavior change for branches that are already in sync (verified the scripts are deterministic and produce no diff on a clean master).
• Runs as a separate parallel job, so it doesn't slow the existing quality job.
• Single-file change (.github/workflows/ci.yml).

🤖 Generated with Claude Code