test(fixture): add no-photos-demo trip for AE4 coverage

A minimal demo trip with no cover_image and a single published journal entry
that has no images — the fixture the trip-page banner AE4 assertion needs
(macro fallback loop finds an entry but no image -> null cover -> no banner
strip). Lives under docs/demo/trips/ like italy-2026-demo, so it is loaded into
the pages tree only for tests and never reaches live content.

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

docs/demo/trips/no-photos-demo/dailies/dailies.md

@@ -0,0 +1,13 @@
+---
+title: Journal
+template: default
+routable: false
+visible: false
+content:
+    items: '@self.children'
+    order:
+        by: date
+        dir: desc
+    filter:
+        published: true
+---