fix: fold in gadfly's own review findings (3 real bugs)

The dogfood swarm reviewed PR #1; folding in the warranted findings
(graded via the gadfly MCP — 18 real / 18 false-positive across the 4
completed reviewers):

- entrypoint.sh: finalize a never-written status file when run.sh skips
  the binary (empty diff / no key / missing binary). The pre-seed stayed
  {started:0, done:false}, so the board showed that model "waiting to
  start" forever and the N/N counter never completed — breaking the
  board's own "tell when everything is finished" invariant.
  (glm-5.2, correctness — the strongest finding.)
- main.go: recover() in the per-lens goroutine. A panic previously
  crashed the whole binary (killing every other lens's output) and left
  the lens stuck "running" on the board. Now it's recorded as an errored
  result and the lens is marked finished. (glm-5.2 + minimax-m3.)
- status-board.sh: coerce a non-numeric GADFLY_STATUS_POLL_SECS back to
  12. Under `set -uo pipefail` a bad `sleep "$POLL"` failed silently and
  the loop spun, hammering the Gitea API. (glm-5.2, error-handling.)

The remaining real findings (sanitizer collision, page-10 pagination,
markdown-injection via PR-controlled lens names, cosmetic blank line)
were graded trivial and left as-is — documented in the finding notes.

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

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/status-board.sh

@@ -29,6 +29,11 @@ set -uo pipefail
 : "${GADFLY_STATUS_DIR:?GADFLY_STATUS_DIR required}"
 
 POLL="${GADFLY_STATUS_POLL_SECS:-12}"
+# Guard against a non-numeric poll interval: with `set -uo pipefail` (no set -e)
+# a bad `sleep "$POLL"` would fail silently and the `while :` loop would spin,
+# hammering the Gitea API. Coerce anything non-integer (or <1) back to 12.
+case "$POLL" in ''|*[!0-9]*) POLL=12 ;; esac
+[ "$POLL" -ge 1 ] 2>/dev/null || POLL=12
 DONE_FILE="${GADFLY_STATUS_DIR}/.done"
 MARKER="<!-- gadfly-status-board -->"
 API_TIMEOUT="--connect-timeout 20 --max-time 30"