pr-implementlisted

# PR Implement Skill Fork-based implementation for open source contributions with mandatory isolation check. ## Overview Execute a contribution plan with fork isolation. Ensures PRs are clean and focused by running isolation checks before and during implementation. **Input**: Plan artifact from `$plan` (after `$pr-research`) or repo URL **When to Use**: - Implementing a planned OSS contribution - Need isolation enforcement for clean PRs - After completing `$pr-research` and `$plan` **When NOT to Use**: - Internal project work (use `$implement`) - Haven't planned yet (run `$pr-research` then `$plan` first) --- ## Workflow ``` -1. Prior Work Check -> BLOCKING: Check for competing PRs 0. Input Discovery -> Find plan artifact or repo 1. Fork Setup -> Ensure fork exists and is current 2. Worktree Creation -> Create isolated worktree 3. Isolation Pre-Check -> BLOCK if mixed concerns 4. Implementation -> Execute plan 5. Isolation Post-Check -> BLOCK if scope creep 6. Commit Preparation -> Stage with proper commit type 7. Handoff -> Ready for $pr-prep ``` --- ## Phase -1: Prior Work Check (BLOCKING) ```bash # Search for open PRs on this topic gh pr list -R <owner/repo> --state open --search "<topic>" --limit 10 # Check target issue status gh issue view <issue-number> -R <repo> --json state,assignees ``` | Finding | Action | |---------|--------| | Open PR exists | Coordinate or wait | | Issue assigned | Coordin