test: /review hardening — NOT-READY env isolation, workdir cleanup, perf

Applied from the adversarial subagent pass during /review on this branch:

- test/benchmark-cli.test.ts — new "NOT READY path fires when auth env
  vars are stripped" test. The default dry-run test always showed OK on
  dev machines with auth, hiding regressions in the remediation-hint
  branch. Stripped env (no auth vars, HOME→empty tmpdir) now force-
  exercises gpt + gemini NOT READY paths and asserts every NOT READY
  line includes a concrete remediation hint (install/login/export).
  (claude adapter's os.homedir() call is Bun-cached; the 2-of-3 adapter
  coverage is sufficient to exercise the branch.)

- test/taste-engine.test.ts — session-cap test rewritten to seed the
  profile with 50 entries + one real CLI call, instead of 55 sequential
  subprocess spawns. Same coverage (FIFO eviction at the boundary), ~5s
  faster CI time. Also pins first-casing-wins on the Geist/GEIST merge
  assertion — bumpPref() keeps the first-arrival casing, so the test
  documents that policy.

- test/skill-e2e-benchmark-providers.test.ts — workdir creation moved
  from module-load into beforeAll, cleanup added in afterAll. Previous
  shape leaked a /tmp/bench-e2e-* dir every CI run.

- test/publish-dry-run.test.ts — removed unused empty test/helpers
  mkdirSync from the sandbox setup. The bin doesn't import from there,
  so the empty dir was a footgun for future maintainers.

- test/helpers/providers/gpt.ts — expanded the inline comment on
  `--skip-git-repo-check` to explicitly note that `-s read-only` is now
  load-bearing safety (the trust prompt was the secondary boundary;
  removing read-only while keeping skip-git-repo-check would be unsafe).

Net: 45 passing tests (was 44), session-cap test 5s faster, one real
regression surface covered that didn't exist before.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

test/taste-engine.test.ts

@@ -208,13 +208,16 @@ describe('taste-engine: dimension extraction', () => {
     expect(p.dimensions.aesthetics.approved[0].value).toBe('brutalist');
   });
 
-  test('value matching is case-insensitive', () => {
+  test('value matching is case-insensitive (first casing wins)', () => {
     run(['approved', 'v1', '--reason', 'fonts: Geist']);
     run(['approved', 'v2', '--reason', 'fonts: GEIST']);
     const p = readProfile();
     // Should merge into a single entry
     expect(p.dimensions.fonts.approved).toHaveLength(1);
     expect(p.dimensions.fonts.approved[0].approved_count).toBe(2);
+    // Canonical value is the first-arrival casing. bumpPref() stores value on
+    // insert and never overwrites on subsequent bumps.
+    expect(p.dimensions.fonts.approved[0].value).toBe('Geist');
   });
 
   test('unknown dimension labels are silently ignored', () => {
@@ -231,14 +234,33 @@ describe('taste-engine: dimension extraction', () => {
 
 describe('taste-engine: session cap', () => {
   test('sessions truncate to last 50 entries (FIFO)', () => {
-    for (let i = 0; i < 55; i++) {
-      run(['approved', `v${i}`, '--reason', 'fonts: Geist']);
-    }
+    // Seed the profile with 50 existing sessions, then one real CLI call writes
+    // the 51st → the oldest must drop. Avoids 55 sequential subprocess spawns.
+    const seededSessions = Array.from({ length: 50 }, (_, i) => ({
+      ts: new Date(Date.now() - (50 - i) * 1000).toISOString(),
+      action: 'approved' as const,
+      variant: `seed-${i}`,
+    }));
+    writeProfile({
+      version: 1,
+      updated_at: new Date().toISOString(),
+      dimensions: {
+        fonts: { approved: [], rejected: [] },
+        colors: { approved: [], rejected: [] },
+        layouts: { approved: [], rejected: [] },
+        aesthetics: { approved: [], rejected: [] },
+      },
+      sessions: seededSessions,
+    });
+    const r = run(['approved', 'new-one', '--reason', 'fonts: Geist']);
+    expect(r.status).toBe(0);
     const p = readProfile();
     expect(p.sessions).toHaveLength(50);
-    // Last 5 should be preserved, first 5 dropped
-    expect(p.sessions[0].variant).toBe('v5');
-    expect(p.sessions[49].variant).toBe('v54');
+    // The oldest seed (seed-0) must have been evicted FIFO; seed-1 is now first;
+    // the new entry is last.
+    expect(p.sessions[0].variant).toBe('seed-1');
+    expect(p.sessions[48].variant).toBe('seed-49');
+    expect(p.sessions[49].variant).toBe('new-one');
   });
 });