feat: await support in browse js/eval + contributor mode v2 (#104)

* feat: support await in $B js and eval commands

Auto-wrap await expressions in async IIFE context so
$B js "await fetch(...)" works without SyntaxError.

- hasAwait() strips comments before detection
- js: expression wrapping (async()=>(expr))()
- eval: smart wrapping — single-line=expression, multi-line=block
- 6 new unit tests covering async, false-positive, and return semantics

* feat: redesign contributor mode — periodic reflection with 0-10 rating

Replace passive "report when things break" with active reflection:
- Rate gstack experience 0-10 at workflow step boundaries
- Historical calibration example (await bug) anchors the reporting bar
- "What would make this a 10" field focuses on actionable improvements
- Removed category lists in favor of judgment-based assessment

* test: add deterministic contributor mode preamble validation

40 new skill-validation tests (4 checks × 10 skills) verify:
- 0-10 rating scale present
- Calibration example present
- "What would make this a 10" field present
- Periodic reflection (not per-command)

Update existing E2E contributor eval for new report format.

* chore: bump version and changelog (v0.4.2)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: improve contributor mode + qa-quick E2E reliability

Contributor mode:
- Add "do not truncate" directive to template — agent was stopping
  after "My rating" without completing Steps/Raw output/What would
  make this a 10 sections
- Restore assertions for Steps to reproduce and Date footer

QA quick:
- Make test server URL prominent: top of prompt, explicit "already
  running" and "do NOT discover ports" instructions
- Bump session timeout 180s→240s and test timeout 240s→300s
- Set B= at top of prompt (was buried in prose)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: use flexible assertions for contributor mode E2E

Agent writes thorough reports with creative section names
("Repro Steps" vs "Steps to reproduce"). Match intent not formatting:
- /repro|steps to reproduce/ for reproduction steps
- /date.*2026/ for date footer presence

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: add E2E eval failure blame protocol

"Not related to our changes" is an extraordinary claim that requires
extraordinary proof. When evals fail during /ship:

1. Run the same eval on main — prove it fails there too
2. If it passes on main, it IS your change — trace the blame
3. If you can't verify, say "unverified" not "pre-existing"

Added to CLAUDE.md and as a comment in skill-e2e.test.ts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: update CONTRIBUTING.md and BROWSER.md for v0.4.2

CONTRIBUTING.md: update contributor mode description — now describes
periodic 0-10 reflection loop instead of passive friction detection.

BROWSER.md: add js/eval async documentation — await expressions are
auto-wrapped in async context, single-line eval returns values directly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: restore v0.4.2 changelog entries lost during cherry-pick conflict

The base branch detection entries from main were dropped when resolving
the CHANGELOG conflict — should have merged both sets, not replaced.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

test/skill-e2e.test.ts

@@ -13,6 +13,11 @@ import * as os from 'os';
 const ROOT = path.resolve(import.meta.dir, '..');
 
 // Skip unless EVALS=1. Session runner strips CLAUDE* env vars to avoid nested session issues.
+//
+// BLAME PROTOCOL: When an eval fails, do NOT claim "pre-existing" or "not related
+// to our changes" without proof. Run the same eval on main to verify. These tests
+// have invisible couplings — preamble text, SKILL.md content, and timing all affect
+// agent behavior. See CLAUDE.md "E2E eval failure blame protocol" for details.
 const evalsEnabled = !!process.env.EVALS;
 const describeE2E = evalsEnabled ? describe : describe.skip;
 
@@ -322,10 +327,16 @@ File a contributor report about this issue. Then tell me what you filed.`,
     const logFiles = fs.readdirSync(logsDir).filter(f => f.endsWith('.md'));
     expect(logFiles.length).toBeGreaterThan(0);
 
+    // Verify new reflection-based format
     const logContent = fs.readFileSync(path.join(logsDir, logFiles[0]), 'utf-8');
     expect(logContent).toContain('Hey gstack team');
     expect(logContent).toContain('What I was trying to do');
     expect(logContent).toContain('What happened instead');
+    expect(logContent).toMatch(/rating/i);
+    // Verify report has repro steps (agent may use "Steps to reproduce", "Repro Steps", etc.)
+    expect(logContent).toMatch(/repro|steps to reproduce|how to reproduce/i);
+    // Verify report has date/version footer (agent may format differently)
+    expect(logContent).toMatch(/date.*2026|2026.*date/i);
 
     // Clean up
     try { fs.rmSync(contribDir, { recursive: true, force: true }); } catch {}
@@ -424,16 +435,20 @@ describeE2E('QA skill E2E', () => {
 
   test('/qa quick completes without browse errors', async () => {
     const result = await runSkillTest({
-      prompt: `You have a browse binary at ${browseBin}. Assign it to B variable like: B="${browseBin}"
+      prompt: `B="${browseBin}"
+
+The test server is already running at: ${testServer.url}
+Target page: ${testServer.url}/basic.html
 
 Read the file qa/SKILL.md for the QA workflow instructions.
 
 Run a Quick-depth QA test on ${testServer.url}/basic.html
 Do NOT use AskUserQuestion — run Quick tier directly.
+Do NOT try to start a server or discover ports — the URL above is ready.
 Write your report to ${qaDir}/qa-reports/qa-report.md`,
       workingDirectory: qaDir,
       maxTurns: 35,
-      timeout: 180_000,
+      timeout: 240_000,
       testName: 'qa-quick',
       runId,
     });
@@ -448,7 +463,7 @@ Write your report to ${qaDir}/qa-reports/qa-report.md`,
     }
     // Accept error_max_turns — the agent doing thorough QA work is not a failure
     expect(['success', 'error_max_turns']).toContain(result.exitReason);
-  }, 240_000);
+  }, 300_000);
 });
 
 // --- B5: Review skill E2E ---

test/skill-validation.test.ts

@@ -496,6 +496,44 @@ describe('v0.4.1 preamble features', () => {
   }
 });
 
+// --- Contributor mode preamble structure validation ---
+
+describe('Contributor mode preamble structure', () => {
+  const skillsWithPreamble = [
+    'SKILL.md', 'browse/SKILL.md', 'qa/SKILL.md',
+    'qa-only/SKILL.md',
+    'setup-browser-cookies/SKILL.md',
+    'ship/SKILL.md', 'review/SKILL.md',
+    'plan-ceo-review/SKILL.md', 'plan-eng-review/SKILL.md',
+    'retro/SKILL.md',
+  ];
+
+  for (const skill of skillsWithPreamble) {
+    test(`${skill} has 0-10 rating in contributor mode`, () => {
+      const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
+      expect(content).toContain('0 to 10');
+      expect(content).toContain('My rating');
+    });
+
+    test(`${skill} has calibration example`, () => {
+      const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
+      expect(content).toContain('Calibration');
+      expect(content).toContain('the bar');
+    });
+
+    test(`${skill} has "what would make this a 10" field`, () => {
+      const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
+      expect(content).toContain('What would make this a 10');
+    });
+
+    test(`${skill} uses periodic reflection (not per-command)`, () => {
+      const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
+      expect(content).toContain('workflow step');
+      expect(content).not.toContain('After you use gstack-provided CLIs');
+    });
+  }
+});
+
 describe('Enum & Value Completeness in review checklist', () => {
   const checklist = fs.readFileSync(path.join(ROOT, 'review', 'checklist.md'), 'utf-8');