feat(trip): one-liner, description & retina cover on trip list + page

Give trips an optional one-liner (header.tagline) and description (markdown
content), surface them where they help, and fix the soft cover image — all
editable from admin.

- U1: header.cover_image blueprint field → pagemediaselect media picker.
- U2: new macros/cover.html.twig — single source for cover resolution
  (author-selected → first journal image → none; missing file falls back)
  and retina rendering (1x/2x cropResize + srcset). Merged resolve+render
  into one macro since Twig macros can't return a Medium object.
- U3: trip-list card renders the one-liner (when set) and the retina cover.
- U4: trip-page in-column header gains the one-liner, an expandable
  description, and a thin banner strip — gated behind a trip_header_extras
  partial flag (default off) so the shared home active-trip view is
  unchanged (R12/KTD4).
- U5: styles for the card/header one-liner, collapsible description
  (max-height preview, not line-clamp, so it holds across paragraphs) and
  the banner, with a mobile banner-height reduction.

Covers R1–R15. Verified with new Playwright specs + full trip/home/maps
regression against an isolated worktree dev server.

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

themes/intotheeast/blueprints/trip.yaml

@@ -38,10 +38,9 @@ form:
               help: 'Leave blank if trip is ongoing'
 
             header.cover_image:
-              type: text
+              type: pagemediaselect
-              label: 'Cover Image Filename'
+              label: 'Cover Image'
-              placeholder: 'cover.jpg'
+              help: 'Pick from images uploaded to this trip page. Shown on the trips listing and the trip-page banner. Falls back to the first journal entry photo if left unset.'
-              help: 'Used in the trips listing page'
 
             header.album_url:
               type: text

themes/intotheeast/css/style.css

@@ -950,6 +950,66 @@ body::after {
     color: var(--color-ink-muted);
 }
 
+/* ── Trip page header extras: one-liner, description, banner ──────────────────── */
+
+.home-trip-tagline {
+    font-size: var(--text-md);
+    line-height: var(--leading-snug);
+    color: var(--color-ink-2);
+    margin: 0 0 var(--space-2);
+}
+
+.trip-header-desc {
+    margin: var(--space-3) 0 var(--space-4);
+}
+
+.trip-header-desc-body {
+    font-size: var(--text-sm);
+    line-height: var(--leading-normal);
+    color: var(--color-ink-2);
+}
+
+.trip-header-desc-body > :first-child { margin-top: 0; }
+.trip-header-desc-body > :last-child { margin-bottom: 0; }
+.trip-header-desc-body p { margin: 0 0 var(--space-2); }
+
+/* Collapsed preview ≈3 lines. Uses max-height (not -webkit-line-clamp) so it
+   holds across the multiple <p> that markdown content renders. */
+.trip-header-desc[data-collapsed="true"] .trip-header-desc-body {
+    max-height: 4.8em;
+    overflow: hidden;
+}
+
+.trip-header-desc-toggle {
+    display: inline-block;
+    margin-top: var(--space-1);
+    padding: 0;
+    background: none;
+    border: none;
+    font: inherit;
+    font-size: var(--text-sm);
+    color: var(--color-accent);
+    cursor: pointer;
+}
+
+.trip-header-desc-toggle:hover { color: var(--color-accent-hover); }
+
+.trip-header-banner {
+    width: 100%;
+    height: 200px;
+    margin: var(--space-4) 0 0;
+    border-radius: var(--radius-md);
+    overflow: hidden;
+    background: var(--color-border);
+}
+
+.trip-header-banner img {
+    width: 100%;
+    height: 100%;
+    object-fit: cover;
+    display: block;
+}
+
 /* ── Trip page filter bar ────────────────────────────────────────────────────── */
 
 .feed-sort-bar {
@@ -1045,6 +1105,7 @@ body::after {
     .home-map-col { position: static; height: 40vh; align-self: stretch; }
     .home-map { height: 40vh; }
     .home-feed-col { padding: var(--space-6) var(--space-5); }
+    .trip-header-banner { height: 130px; }
 }
 
 /* ── Past trips archive ──────────────────────────────────────────────────────── */
@@ -1114,6 +1175,13 @@ body::after {
     margin-bottom: var(--space-2);
 }
 
+.trip-card-tagline {
+    font-size: var(--text-sm);
+    line-height: var(--leading-snug);
+    color: var(--color-ink-muted);
+    margin: 0 0 var(--space-3);
+}
+
 .trip-card-meta {
     display: flex;
     gap: var(--space-4);

themes/intotheeast/templates/macros/cover.html.twig

@@ -0,0 +1,45 @@
+{#
+  Shared trip cover: one source of truth for cover resolution + retina
+  rendering, used by both the trip-list card (trips.html.twig) and the
+  trip-page banner strip (trip-feed-col.html.twig) so the two surfaces
+  cannot drift (KTD2).
+
+  Resolution (R7 / R11):
+    1. author-selected header.cover_image, when it resolves to page media;
+    2. else the first published journal entry's first image;
+    3. else nothing.
+  A set-but-missing cover_image (deleted/moved file) is `is not defined` in
+  page media, so it falls through to the auto-pick rather than rendering a
+  broken image (R11).
+
+  Twig macros can only emit strings — they cannot return a Medium object —
+  so resolution and rendering live together in one macro: it emits the
+  wrapper + retina <img> when a cover exists, and nothing at all when none
+  does (which gives R9/AE4 a clean text-only header for free).
+
+  Retina (R6 / R14): two explicit cropResize derivatives (1x at w×h, 2x at
+  2w×2h) as an explicit `srcset` with w-descriptors; `alt` is the trip title.
+#}
+{% macro render(trip_page, alt, w, h, wrapper_class, sizes) %}
+{%- set cover = null -%}
+{%- if trip_page.header.cover_image and trip_page.media[trip_page.header.cover_image] is defined -%}
+    {%- set cover = trip_page.media[trip_page.header.cover_image] -%}
+{%- else -%}
+    {%- set dailies_page = grav.pages.find(trip_page.route ~ '/dailies') -%}
+    {%- if dailies_page -%}
+        {%- set first_entry = dailies_page.children.published()|first -%}
+        {%- if first_entry and first_entry.media.images|length > 0 -%}
+            {%- set cover = first_entry.media.images|first -%}
+        {%- endif -%}
+    {%- endif -%}
+{%- endif -%}
+{%- if cover -%}
+<div class="{{ wrapper_class }}">
+    <img src="{{ cover.cropResize(w, h).url }}"
+         srcset="{{ cover.cropResize(w, h).url }} {{ w }}w, {{ cover.cropResize(w * 2, h * 2).url }} {{ (w * 2) }}w"
+         sizes="{{ sizes|default('100vw') }}"
+         alt="{{ alt }}"
+         loading="lazy">
+</div>
+{%- endif -%}
+{% endmacro %}

themes/intotheeast/templates/partials/trip-feed-col.html.twig

@@ -1,8 +1,16 @@
 {% import 'macros/stats.html.twig' as stats_m %}
 {% import 'macros/cycling.html.twig' as cycling_m %}
+{% import 'macros/cover.html.twig' as cover %}
+{# trip_header_extras: gated one-liner + description + banner for the trip-page
+   caller only. Home's active-trip include omits it (`only`), so it defaults off
+   and that header renders exactly as before (KTD4 / R12). #}
+{% set trip_header_extras = trip_header_extras|default(false) %}
 <div class="home-feed-col">
     <div class="home-trip-header">
         <h1 class="home-trip-name">{{ trip_page.title }}</h1>
+        {% if trip_header_extras and trip_page.header.tagline %}
+        <p class="home-trip-tagline">{{ trip_page.header.tagline }}</p>
+        {% endif %}
         {% if trip_page.header.date_start %}
         <p class="trip-dates">
             {{ trip_page.header.date_start|date('d M Y') }}
@@ -13,6 +21,15 @@
             {{ journal_count }} journal {{ journal_count == 1 ? 'entry' : 'entries' }}
             {% if story_count > 0 %} · {{ story_count }} {{ story_count == 1 ? 'story' : 'stories' }}{% endif %}
         </span>
+        {% if trip_header_extras and trip_page.content|striptags|trim %}
+        <div class="trip-header-desc" data-collapsed="true">
+            <div class="trip-header-desc-body">{{ trip_page.content|raw }}</div>
+            <button type="button" class="trip-header-desc-toggle" aria-expanded="false">Read more</button>
+        </div>
+        {% endif %}
+        {% if trip_header_extras %}
+        {{ cover.render(trip_page, trip_page.title, 720, 220, 'trip-header-banner', '100vw') }}
+        {% endif %}
         <div class="trip-filter-bar">
             <div class="trip-filter-group">
                 <button class="trip-filter-btn is-active" data-filter="all" aria-pressed="true">All content</button>
@@ -62,4 +79,27 @@
         });
     });
     </script>
+    {% if trip_header_extras %}
+    <script>
+    document.addEventListener('DOMContentLoaded', function () {
+        document.querySelectorAll('.trip-header-desc').forEach(function (desc) {
+            var body = desc.querySelector('.trip-header-desc-body');
+            var btn  = desc.querySelector('.trip-header-desc-toggle');
+            if (!body || !btn) return;
+            // Drop the toggle when the description already fits the collapsed preview.
+            if (body.scrollHeight <= body.clientHeight + 4) {
+                btn.hidden = true;
+                desc.removeAttribute('data-collapsed');
+                return;
+            }
+            btn.addEventListener('click', function () {
+                var collapsed = desc.getAttribute('data-collapsed') === 'true';
+                desc.setAttribute('data-collapsed', collapsed ? 'false' : 'true');
+                btn.setAttribute('aria-expanded', collapsed ? 'true' : 'false');
+                btn.textContent = collapsed ? 'Show less' : 'Read more';
+            });
+        });
+    });
+    </script>
+    {% endif %}
 </div>

themes/intotheeast/templates/trip.html.twig

@@ -78,7 +78,8 @@
         has_gpx: has_gpx,
         gpx_urls: gpx_urls,
         gps_points: gps_points,
-        show_sort: true
+        show_sort: true,
+        trip_header_extras: true
     } only %}
 </div>
 

themes/intotheeast/templates/trips.html.twig

@@ -1,6 +1,7 @@
 {% extends 'partials/base.html.twig' %}
 
 {% block content %}
+{% import 'macros/cover.html.twig' as cover %}
 <h1 class="trips-heading">Past Trips</h1>
 {% set trips = page.children.published()|sort((a, b) => a.date < b.date ? 1 : -1) %}
 {% if trips|length == 0 %}
@@ -13,21 +14,11 @@
     {% set journal_count = dailies_page ? dailies_page.children.published()|length : 0 %}
     {% set story_count = stories_page ? stories_page.children.published()|length : 0 %}
     <a class="trip-card" href="{{ trip.url }}">
-        {% set cover = null %}
+        {{ cover.render(trip, trip.title, 720, 240, 'trip-card-cover', '(max-width: 700px) 100vw, 360px') }}
-        {% if trip.header.cover_image and trip.media[trip.header.cover_image] is defined %}
-            {% set cover = trip.media[trip.header.cover_image] %}
-        {% elseif dailies_page %}
-            {% set first_entry = dailies_page.children.published()|first %}
-            {% if first_entry and first_entry.media.images|length > 0 %}
-                {% set cover = first_entry.media.images|first %}
-            {% endif %}
-        {% endif %}
-        {% if cover %}
-        <div class="trip-card-cover">
-            <img src="{{ cover.cropResize(720, 240).url }}" alt="{{ trip.title }}" loading="lazy">
-        </div>
-        {% endif %}
         <div class="trip-card-title">{{ trip.title }}</div>
+        {% if trip.header.tagline %}
+        <div class="trip-card-tagline">{{ trip.header.tagline }}</div>
+        {% endif %}
         <div class="trip-card-meta">
             {% if trip.header.date_start %}
             <span class="trip-card-dates">