fix(e2e): resolve flaky haiku display test by checking only last haiku

The Tool Based Generative UI haiku test was exhibiting flaky behavior
where it would sometimes pass and sometimes fail with the same test
conditions. The test was more reliable when run with --headed than
when run headless, suggesting a timing-related issue.

Root cause: The extractMainDisplayHaikuContent() method was concatenating
ALL visible haiku lines from the main display, while the chat extraction
only captured the most recent haiku. When multiple haikus were displayed
simultaneously (due to rendering timing), this caused mismatches.

Fix: Modified extractMainDisplayHaikuContent() to extract only the last
3 lines (the most recent haiku), matching the behavior of the chat
extraction and eliminating timing-related flakiness.

This affects all 10 platform integration tests that use ToolBaseGenUIPage.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: contextablemark

typescript-sdk/apps/dojo/e2e/featurePages/ToolBaseGenUIPage.ts

@@ -73,16 +73,23 @@ export class ToolBaseGenUIPage {
   }
 
   async extractMainDisplayHaikuContent(page: Page): Promise<string> {
+    // Wait for main haiku lines to be present
     const mainDisplayLines = page.locator('[data-testid="main-haiku-line"]');
     const mainCount = await mainDisplayLines.count();
+
+    if (mainCount === 0) {
+      return '';
+    }
+
+    // Take only the last 3 lines (most recent haiku)
+    // Haikus are 3 lines, and they're appended in order
+    const startIndex = Math.max(0, mainCount - 3);
     const lines: string[] = [];
 
-    if (mainCount > 0) {
-      for (let i = 0; i < mainCount; i++) {
-        const haikuLine = mainDisplayLines.nth(i);
-        const japaneseText = await haikuLine.locator('p').first().innerText();
-        lines.push(japaneseText);
-      }
+    for (let i = startIndex; i < mainCount; i++) {
+      const haikuLine = mainDisplayLines.nth(i);
+      const japaneseText = await haikuLine.locator('p').first().innerText();
+      lines.push(japaneseText);
     }
 
     const mainHaikuContent = lines.join('').replace(/\s/g, '');