fix: add Chromium verification step before browse E2E tests

Adds a fast pre-check that Playwright can actually launch Chromium
with --no-sandbox in the CI container. This will fail fast with a
clear error instead of burning API credits on 11-turn agent loops
that can't start the browser.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/evals.yml

@@ -110,6 +110,11 @@ jobs:
 
       - run: bun run build
 
+      # Verify Playwright can launch Chromium (fails fast if sandbox/deps are broken)
+      - name: Verify Chromium
+        if: matrix.suite.name == 'e2e-browse'
+        run: node -e "const {chromium}=require('playwright');(async()=>{const b=await chromium.launch({args:['--no-sandbox']});console.log('Chromium OK');await b.close();})()"
+
       - name: Run ${{ matrix.suite.name }}
         env:
           ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}