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>

test/gbrain-detect-shape.test.ts

@@ -43,7 +43,10 @@ function runDetect(env: Partial<NodeJS.ProcessEnv>): string {
     encoding: "utf-8",
     timeout: 15_000,
     stdio: ["ignore", "pipe", "pipe"],
-    env: { ...process.env, ...env },
+    // GBRAIN_HOME pinned empty: detect honors it (codex D11), and sibling
+    // test files in the same shard set it ambiently — without the pin, the
+    // spawned detect reads the polluter's (or the developer's real) config.
+    env: { ...process.env, GBRAIN_HOME: "", ...env },
   });
 }
 
@@ -52,7 +55,7 @@ function runIsOk(env: Partial<NodeJS.ProcessEnv>): number {
   const r = spawnSync(BUN_BIN, ["run", DETECT_BIN, "--is-ok"], {
     timeout: 15_000,
     stdio: ["ignore", "pipe", "pipe"],
-    env: { ...process.env, ...env },
+    env: { ...process.env, GBRAIN_HOME: "", ...env },
   });
   return r.status ?? 1;
 }