feat(ui): add infinite scroll pagination to chat completions/responses logs table (#2466)

## Summary:

This commit adds infinite scroll pagination to the chat completions and
responses tables.


## Test Plan:
  1. Run unit tests: npm run test
  2. Manual testing: Navigate to chat
  completions/responses pages
  3. Verify infinite scroll triggers when approaching
  bottom
  4. Added playwright tests: npm run test:e2e

llama_stack/ui/e2e/logs-table-scroll.spec.ts

@@ -0,0 +1,61 @@
+import { test, expect } from "@playwright/test";
+
+test.describe("LogsTable Scroll and Progressive Loading", () => {
+  test.beforeEach(async ({ page }) => {
+    // Navigate to the chat completions page
+    await page.goto("/logs/chat-completions");
+
+    // Wait for initial data to load
+    await page.waitForSelector("table tbody tr", { timeout: 10000 });
+  });
+
+  test("should progressively load more data to fill tall viewports", async ({
+    page,
+  }) => {
+    // Set a tall viewport (1400px height)
+    await page.setViewportSize({ width: 1200, height: 1400 });
+
+    // Wait for the table to be visible
+    await page.waitForSelector("table");
+
+    // Wait a bit for progressive loading to potentially trigger
+    await page.waitForTimeout(3000);
+
+    // Count the number of rows loaded
+    const rowCount = await page.locator("table tbody tr").count();
+
+    // With a 1400px viewport, we should have more than the default 20 rows
+    // Assuming each row is ~50px, we should fit at least 25-30 rows
+    expect(rowCount).toBeGreaterThan(20);
+  });
+
+  test("should trigger infinite scroll when scrolling near bottom", async ({
+    page,
+  }) => {
+    // Set a medium viewport
+    await page.setViewportSize({ width: 1200, height: 800 });
+
+    // Wait for initial load
+    await page.waitForSelector("table tbody tr");
+
+    // Get initial row count
+    const initialRowCount = await page.locator("table tbody tr").count();
+
+    // Find the scrollable container
+    const scrollContainer = page.locator("div.overflow-auto").first();
+
+    // Scroll to near the bottom
+    await scrollContainer.evaluate((element) => {
+      element.scrollTop = element.scrollHeight - element.clientHeight - 100;
+    });
+
+    // Wait for loading indicator or new data
+    await page.waitForTimeout(2000);
+
+    // Check if more rows were loaded
+    const newRowCount = await page.locator("table tbody tr").count();
+
+    // We should have more rows after scrolling
+    expect(newRowCount).toBeGreaterThan(initialRowCount);
+  });
+});