fix: pre-landing review fixes (27 specialist findings, 3 critical)

Specialist army findings, all quote-verified before fixing:

Security: careful force-push guard now catches git's plus-refspec force
syntax (git push origin +main carried force with no flag — silently allowed
before) and refspec-form targets (HEAD:main); default-branch matching is
tokenized FIXED-STRING comparison on the full branch path (slashed defaults
like release/2.0 work; no ERE interpolation), glob-safe via noglob. HIGH rm
tier is tokenized too: trailing long options (--no-preserve-root) and /* are
root-class. Stored evidence fingerprints are 40-hex re-validated before
reaching git argv. normalizeForDetection sweeps ALL Unicode format chars
(\p{Cf}: soft hyphens, bidi marks, tag chars) instead of five enumerated
zero-widths. The wiring scanner gains flagless gh pr/issue view patterns. The
release-body banner tripwire diffs against the fetched original so a hostile
pre-existing banner string can't permanently DoS doc updates. Ship/land
evidence checks now pass --expect-cmd (a green `echo ok` recorded under the
label can never mint FRESH); package.json stays allow-listed with the
residual documented.

Performance: gstack-wtree seeds its temp index by COPYING the real index
(stat cache preserved — measured 40x faster than read-tree seeding, identical
hash) with read-tree fallback; evidence uses findLast and one gstack-slug
spawn; the stream pump honors backpressure via drain; careful's pattern block
short-circuits before slug resolution when no pattern file exists.

Testing: the gh-failure envelope test was VACUOUS (killing PATH killed the
bun shebang before the code under test ran) — replaced with a PATH gh shim
that exercises the real branch, plus shimmed happy paths (issue/pr-body/
unparseable JSON); evidence check --all + empty ledger + non-numeric
--max-age (now a usage error, was silent fail-open) covered; HIGH-tier
variants pinned; hook analytics respect GSTACK_HOME so tests stop writing the
operator's real skill-usage.jsonl.

Maintainability: dead exit ternary removed; flagValue deduped into
bin-context; sentinel defusal derived from the banner constants (no invisible
literals — \u escapes only); scratch-repo git fixture extracted to
test/helpers/scratch-repo.ts (one hermetic incantation, three consumers);
shared gstack_hook_log_fire in hook-extract.sh; the dashboard/land diff-scoped
row lists are aligned (codex-review) and drift-pinned.

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

test/review-log.test.ts

@@ -3,6 +3,7 @@ import { execSync, ExecSyncOptionsWithStringEncoding } from 'child_process';
 import * as fs from 'fs';
 import * as path from 'path';
 import * as os from 'os';
+import { gitIn } from './helpers/scratch-repo';
 
 const ROOT = path.resolve(import.meta.dir, '..');
 const BIN = path.join(ROOT, 'bin');
@@ -144,8 +145,7 @@ describe('gstack-wtree', () => {
   function withScratchRepo(fn: (repoDir: string, wtree: () => string) => void) {
     const repoDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gstack-wtree-'));
     try {
-      const git = (args: string) =>
-        execSync(`git -c user.email=t@test -c user.name=t -c commit.gpgsign=false -c tag.gpgsign=false ${args}`, { cwd: repoDir, encoding: 'utf-8', timeout: 10000 });
+      const git = (args: string) => gitIn(repoDir, args);
       git('init -q -b main');
       fs.writeFileSync(path.join(repoDir, 'a.txt'), 'hello\n');
       fs.writeFileSync(path.join(repoDir, '.gitignore'), 'scratch.txt\n');
@@ -177,7 +177,7 @@ describe('gstack-wtree', () => {
     withScratchRepo((repoDir, wtree) => {
       fs.writeFileSync(path.join(repoDir, 'a.txt'), 'edited\n');
       const dirtyFingerprint = wtree();
-      execSync('git -c user.email=t@test -c user.name=t -c commit.gpgsign=false commit -q -am edit', { cwd: repoDir, timeout: 10000 });
+      gitIn(repoDir, 'commit -q -am edit');
       expect(wtree()).toBe(dirtyFingerprint);
     });
   });