Show the whole option preview on native so every line is reachable

On Android, a slow drag inside a preview capped at 240px did not scroll
it, so lines past the cap could not be read. The preview's nested
scroll sits inside the option's Pressable; the same drag scrolls it
once the preview is outside the Pressable. Native now renders the
preview at full height so the chat scroll reaches every line, and a tap
on it still selects the option. Web keeps the 240px cap.

The mock agent's rollout preview is now taller than the cap so the
Android replay can check the last line.

packages/app/e2e/mobile/agent-device/native-question-option-preview-preconditions.md

@@ -0,0 +1,7 @@
+# Native question option preview
+
+`native-question-option-preview.android.ad` checks that every line of a long option preview is reachable on Android. Before replay, open a mock agent prompted with `emit synthetic questions` so its question card shows the first question, on a phone-sized emulator (validated on a 1080×1920 API 35 AVD). The flow opens the `rollout` question, drags slowly up from inside the "Behind feature flag" preview, and asserts the preview's last line is visible.
+
+```sh
+agent-device replay packages/app/e2e/mobile/agent-device/native-question-option-preview.android.ad --platform android --serial emulator-5554
+```

packages/app/e2e/mobile/agent-device/native-question-option-preview.android.ad

@@ -0,0 +1,10 @@
+context platform=android timeout=60000 retries=0
+env APP_ID=sh.paseo.debug
+
+open "${APP_ID}"
+wait "label=\"rollout\"" 20000
+press "label=\"rollout\""
+wait "id=\"question-form-option-preview\"" 10000
+gesture pan 570 1120 0 -440 600
+is visible "text=\"// LAST PREVIEW LINE\""
+close

packages/app/src/components/question-form-card.tsx

@@ -30,7 +30,9 @@ interface QuestionFormCardProps {
 }
 
 const IS_WEB = isWeb;
-const OPTION_PREVIEW_MAX_HEIGHT = 240;
+// Native previews are uncapped: inside the option's Pressable, Android never hands a
+// drag to the preview's nested scroll, so lines past a cap would be unreachable.
+const OPTION_PREVIEW_MAX_HEIGHT = IS_WEB ? 240 : undefined;
 
 function getQuestionInputPlaceholder({
   question,

packages/server/src/server/agent/providers/mock-load-test-agent.ts

@@ -278,6 +278,8 @@ const ROLLOUT_FLAG_PREVIEW = [
   'if (flags.enabled("new-surface")) {',
   "  render(<NewSurface />);",
   "}",
+  ...Array.from({ length: 40 }, (_, i) => `// rollout step ${i + 1}`),
+  "// LAST PREVIEW LINE",
 ].join("\n");
 
 function parseMockQuestionPrompt(prompt: AgentPromptInput): MockQuestionPromptRequest | null {