PR #58 merged: fix(ci): unpin retired Claude models, let reviews actually post

Two silent failures in the Claude workflows, fixed in both the repo's own workflows and the published stubs:

1. Retired model pin. claude-code-review.yml pinned claude-sonnet-4-20250514, which was retired 2026-06-15 — review runs have been pointing at a dead model since. claude.yml + stub pinned legacy claude-opus-4-5. Pins dropped entirely so the action tracks its current default and this can't rot again.

2. Reviews could never post. The review workflow grants pull-requests: read / issues: read, but the prompt instructs Claude to comment via gh pr comment — a read-only token can't do that, so runs went green with no comment ever posted (same failure mode previously found on crunch). Bumped to write in the repo workflow and the stub.

Left types: [opened] alone — CHANGELOG says opened-only was a deliberate API-cost decision.

Full pest suite green (63 passed).