feat: live status-board comment + full-fleet dogfood (#1)

Phase 3: one consolidated, live-updating PR comment aggregating every
model's per-lens progress (queued -> running -> finished + verdict), so
the swarm's progress is visible at a glance and a watcher can tell when
it's done. Opt-in statusWriter in the binary (atomic writes) + a
background status-board.sh renderer wired through entrypoint.sh; default
on, GADFLY_STATUS_BOARD=0 to disable.

Also restores gadfly's dogfood swarm to the full cloud fleet (9 cloud +
M5; M1 dropped as too slow) matching mort, and folds in the 3 real bugs
the swarm found on its own PR (skip-binary stuck-waiting, panic-stuck
lens, busy-loop on bad poll interval). All 36 findings graded via the
gadfly MCP (18 real / 18 false-positive).

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>

Dockerfile

@@ -28,5 +28,5 @@ RUN apk add --no-cache bash git curl jq ca-certificates
 COPY --from=build /out/gadfly /usr/local/bin/gadfly
 COPY scripts /app/scripts
 COPY entrypoint.sh /entrypoint.sh
-RUN chmod +x /entrypoint.sh /app/scripts/run.sh /usr/local/bin/gadfly
+RUN chmod +x /entrypoint.sh /app/scripts/run.sh /app/scripts/status-board.sh /usr/local/bin/gadfly
 ENTRYPOINT ["/entrypoint.sh"]