Add PR workflow and release management handlers. Total tools: 22.
New tools:
- blue_pr_create: Create PR with enforced develop base branch
- blue_pr_verify: Verify test plan checkboxes (CLI/browser/manual)
- blue_pr_check_item: Mark test plan item as verified
- blue_pr_check_approvals: Check for user approval
- blue_pr_merge: Squash-merge with precondition enforcement
- blue_release_create: Semantic versioning with RFC analysis
All handlers use gh CLI for GitHub operations.
Blue's voice in all error messages.
16 tests passing.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>