test(trip): tighten description-clamp assertion + correct R11 coverage note

- trip-header.spec.js: replace the vacuous `toContainText('finally made
  sense')` (the tail text is in the DOM even while collapsed) with real
  clamp/un-clamp assertions — clientHeight < scrollHeight when collapsed,
  clientHeight >= scrollHeight once expanded — so the test actually proves the
  toggle changes visibility.
- trips-list.spec.js: the header comment claimed R11 coverage no fixture
  provided. Note that R11 (set-but-unresolvable cover_image) shares the exact
  else-branch the R7/AE3 fallback test exercises, so it's covered by
  construction in the shared cover macro.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RDS6t8wcpbwKvvrxykVQ5K

tests/ui/trip/trip-header.spec.js

@@ -36,6 +36,11 @@ test('U4/R13: description is clamped to a preview and expands to full text', asy
     await expect(desc).toHaveAttribute('data-collapsed', 'true');
     await expect(btn).toBeVisible();
 
+    // Collapsed: the body is genuinely clamped — visible height is shorter than
+    // its full content (the max-height:4.8em preview actually hides overflow).
+    const clampedWhenCollapsed = await body.evaluate((el) => el.clientHeight < el.scrollHeight);
+    expect(clampedWhenCollapsed).toBe(true);
+
     const collapsedH = (await body.boundingBox()).height;
     await btn.click();
 
@@ -43,7 +48,10 @@ test('U4/R13: description is clamped to a preview and expands to full text', asy
     await expect(btn).toHaveText('Show less');
     const expandedH = (await body.boundingBox()).height;
     expect(expandedH).toBeGreaterThan(collapsedH);
-    await expect(body).toContainText('finally made sense'); // tail of the full description
+    // Expanded: the clamp is gone — the full text is now actually visible, not
+    // merely present in the DOM (which it was even while collapsed).
+    const unclampedWhenExpanded = await body.evaluate((el) => el.clientHeight >= el.scrollHeight - 1);
+    expect(unclampedWhenExpanded).toBe(true);
 });
 
 // ── R9/AE3: banner uses the first journal image (no cover_image set) ───────────

tests/ui/trip/trips-list.spec.js

@@ -1,5 +1,8 @@
 // @ts-check
-// Tests: U3 — trip-list card one-liner + retina cover (R5, R6, R7, R11, R14)
+// Tests: U3 — trip-list card one-liner + retina cover (R5, R6, R7, R14)
+// R11 (set-but-unresolvable cover_image falls back) shares the exact else-branch
+// exercised by the R7/AE3 fallback test below; it is covered by construction in
+// the shared cover macro rather than by a dedicated fixture here.
 const { test, expect } = require('@playwright/test');
 
 const DEMO_HREF = '/trips/italy-2026-demo';   // has a tagline, no cover_image (entry-image fallback)