fix: adversarial review fixes (Claude + Codex cross-model passes)

Both adversarial passes ran against the wave; every FIXABLE finding landed
with a regression test:

- probeTimeoutMs clamps to >=1ms: a fractional override floored to 0, and
  execFileSync treats timeout:0 as NO timeout — the probe that exists to
  bound hangs could hang forever (found by both models independently).
- /ship silent hook install now requires the hooks dir to live inside
  .git: with core.hooksPath (husky's COMMITTED .husky/), the chaining
  installer would have renamed the team's committed pre-push and written a
  machine-local wrapper into the working tree (found by both models).
- gstack-config gbrain-refresh accepts the "timeout" status — the last
  consumer still gating on literal "ok" (Codex); gstack-gbrain-detect's
  config-derived fields honor GBRAIN_HOME so the detection JSON can't
  report status ok alongside config_exists false (Codex).
- prepush: a remote sha absent locally (shallow clone / stale fetch) falls
  back to the merge-base/empty-tree range — scans MORE, never blocks a
  legitimate push into training users toward --no-verify.
- dashboards: curl's own 000 no longer doubles to "HTTP 000000"; the
  community dashboard flags stale snapshots like the security one; array
  sections parse via jq (the sed/grep loops truncated at the first ']');
  the no-jq marker grep tolerates whitespace.
- telemetry: multi-line redactor output nulls the field instead of
  corrupting the JSONL record; setup's hint fires only when the config key
  is genuinely unset (an explicit false is a recorded decline); the /ship
  prompt marker honors GSTACK_HOME.

Kept as designed (cross-model tension noted): Bearer stays MEDIUM in the
prepush gate — a HIGH Bearer would block every docs example; the entropy
validator can't eliminate that FP class, and MEDIUM warns visibly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

setup

@@ -1493,7 +1493,12 @@ fi
 # checkout, the wrong repo to install it into. /ship offers the install once
 # at the moment of relevance (first push) and silently installs in any repo
 # where redact_prepush_hook=true. This hint is setup's whole involvement.
-if [ "$("$GSTACK_CONFIG" get redact_prepush_hook 2>/dev/null || echo false)" != "true" ]; then
+# Hint only when UNSET — an explicit "false" is a recorded decline and must
+# not be re-nagged on every setup run (adversarial review finding 11).
+# `gstack-config get` defaults absent keys to "false", which is
+# indistinguishable from a decline — test key presence in the config file.
+_GSTACK_CFG_FILE="${GSTACK_HOME:-$HOME/.gstack}/config.yaml"
+if ! grep -q '^redact_prepush_hook:' "$_GSTACK_CFG_FILE" 2>/dev/null; then
   log ""
   log "Tip: gstack can block pushes containing credentials (per-repo git hook)."
   log "     Enable once: gstack-config set redact_prepush_hook true — /ship"