Turns the manual QA ask ("verify DiffView + CodeBlock horizontal-scroll
on-device with a populated diff") into two automated layers:
1. Unit (deterministic, runs in `npm test` now): extracted the shared
ScrollView props into src/lib/scroll-config.ts (WIDE_CONTENT_SCROLL_CONFIG)
so DiffView.tsx and CodeBlock.tsx spread the SAME plain object their tests
assert on — no react-native-renderer needed. Added a source-scan
regression test (wide-content-scroll.regression.test.ts) that fails if
either component loses its ScrollView wiring or reintroduces
numberOfLines truncation.
2. E2E (Maestro): .maestro/flows/diff-scroll.yaml opens a session with a
pre-seeded wide edit-diff tool call and a wide fenced code block, then
swipes each horizontal ScrollView left and asserts the off-screen marker
text becomes visible. mock-opencode-server.ts gained a --seed-diff mode
that serves this session via GET /session/:id/message (pre-existing
history), not SSE — issue #90 (a separate SSE-render bug) is being fixed
independently, and this flow must not depend on it landing first. Wired
the new flow + port 4100 into run-e2e-flows.sh and activation-e2e.yml.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
