## Summary
- add a reusable skill for the Dependabot PR rollup workflow
- place it under `.agents/skills/` for cross-client discovery
- keep the skill aligned with the Agent Skills standard and
client-agnostic
## Details
- adds `.agents/skills/dependabot-pr-rollup/SKILL.md`
- documents the workflow for:
- finding open Dependabot PRs
- comparing PR heads to their base branch
- replaying only net dependency changes in a fresh worktree
- running `npm run all`
- optionally committing, pushing, and opening a PR
## Notes
- `.agents/skills/` is the shared interoperability location used across
multiple coding agents
- no code changes
- tests not run (documentation-only skill)
