test(e2e): Playwright photos-ready flow + visual evidence (#65)

Drive batch → pick calibration → Mask (Black) → Axis → Measure Calculate →
Photos ready against set1-48x2 fixtures on local vite preview. Capture
screenshots under tests/e2e/artifacts/; commit README + small evidence JPEGs.

.gitignore

@@ -35,3 +35,11 @@ images/
 
 # Logs
 *.log
+
+# Playwright e2e (#65) — keep README; ignore churn
+frontend/tests/e2e/artifacts/*.png
+frontend/tests/e2e/artifacts/run-log.txt
+frontend/tests/e2e/test-results/
+frontend/tests/e2e/playwright-report/
+frontend/blob-report/
+frontend/playwright/.cache/