feat: claude-code reviewer engine (#2)

Phase 1: a second review engine alongside the majordomo agent loop. For
each lens, shell out to the Claude Code CLI (`claude -p --output-format
json`) inside the checked-out repo so it verifies findings with its own
read tools, then reuse gadfly's verdict-parse + recheck + consolidate +
emit pipeline. Select via GADFLY_MODELS `claude-code`/`claude-code/<model>`;
auth via CLAUDE_CODE_OAUTH_TOKEN (no --bare) else ANTHROPIC_API_KEY;
read-only by default; GADFLY_CLAUDE_* knobs. Dockerfile bundles Node +
@anthropic-ai/claude-code. Also bumped the dogfood pin to the status-board
image (PR #2 was the first dogfood with the live board + full fleet).

Folded in the swarm's own review findings: minimal subprocess env (no
GITEA_TOKEN leak to the CLI), runPass robustness (ctx/empty-result/runErr),
process-group cleanup on timeout, rune-safe error truncation, and
engine-neutral prompts (also de-mort-ified the recheck prompt). 66 findings
graded via the gadfly MCP.

gofmt clean, go vet quiet, go build + go test -race green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Steve Dudenhoeffer <steve@stevedudenhoeffer.com>
Co-committed-by: Steve Dudenhoeffer <steve@stevedudenhoeffer.com>

.gitea/workflows/adversarial-review.yml

@@ -45,7 +45,7 @@ jobs:
     # every PR with the 3-lens suite — the slow local lane dominates wall time.
     timeout-minutes: 90
     steps:
-      - uses: docker://gitea.stevedudenhoeffer.com/steve/gadfly:sha-d7f364d
+      - uses: docker://gitea.stevedudenhoeffer.com/steve/gadfly:sha-c3d09d3
         env:
           GITEA_API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
           GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}