feat(roadmap): 'In motion right now' strip + subtitle copy + admin helper

New <RoadmapInMotion> component renders between the dispatch banner
and the route's section header. Pulls the most-recent shipping item
(same selection rule the .rr-current marker uses) and prints the
first sentence of its description as a 18px serif italic line
preceded by an 'IN MOTION RIGHT NOW' tracked eyebrow.

A member who only spends 5 seconds on /roadmap now still walks away
with a sentence about what just shipped — no scroll, no hover.

firstSentenceOf() is the obvious regex against the first
[.!?](?=\s|$). Bails to the 200-char slice if no sentence boundary
fits (covers 'Dr.' / 'e.g.' confusables). Returns '' on null. The
strip hides itself entirely when there's no shipping item, or when
the shipping item has no description text.

Page subtitle: 'Hover any milestone for the full story.' →
'Tap or hover any milestone for the full story.' — touch devices
don't have hover, and the kind of detail that says we're paying
attention.

Admin description-field gains a helper note: 'For shipping items:
the first sentence appears on /roadmap as the "In motion right now"
line. Make it count.' Nudges good first-sentence writing without
adding a new field to maintain.

Banner margin under the dispatch banner reduces 56 → 40px because
the in-motion strip carries its own 36px bottom margin to the route.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/RoadmapInMotion.astro

@@ -0,0 +1,69 @@
+---
+import type { RoadmapItemWithAttribution } from '../lib/db';
+
+interface Props {
+  items: RoadmapItemWithAttribution[];
+}
+
+const { items } = Astro.props;
+
+/** First sentence of a description — naive but matches the user's needs.
+ *  Returns '' for null/empty input. Falls back to a 200-char slice if no
+ *  sentence-ending punctuation is found in a reasonable window. */
+function firstSentenceOf(text: string | null): string {
+  if (!text) return '';
+  const trimmed = text.trim();
+  const match = trimmed.match(/^[^.!?]*[.!?](?=\s|$)/);
+  return match ? match[0] : trimmed.slice(0, 200);
+}
+
+// Most recent shipping item, in display_order (same selection rule as
+// the .rr-current marker on the route).
+let currentItem: RoadmapItemWithAttribution | null = null;
+items.forEach((it) => { if (it.status === 'shipping') currentItem = it; });
+
+const line = currentItem ? firstSentenceOf(currentItem.description) : '';
+const visible = !!currentItem && line.length > 0;
+---
+{visible && (
+  <div class="rr-in-motion">
+    <span class="rr-in-motion-eyebrow">In motion right now</span>
+    <p class="rr-in-motion-line">{line}</p>
+  </div>
+)}
+
+<style>
+  .rr-in-motion {
+    display: flex;
+    align-items: baseline;
+    gap: 18px;
+    margin-bottom: 36px;
+    padding: 0 4px;
+  }
+  .rr-in-motion-eyebrow {
+    font-family: var(--font-sans);
+    font-size: 10px;
+    letter-spacing: 1.4px;
+    text-transform: uppercase;
+    color: var(--on-surface-muted);
+    flex-shrink: 0;
+  }
+  .rr-in-motion-line {
+    font-family: var(--font-serif);
+    font-style: italic;
+    font-size: 18px;
+    line-height: 1.4;
+    color: var(--on-surface);
+    margin: 0;
+    max-width: 720px;
+  }
+
+  @media (max-width: 767px) {
+    .rr-in-motion {
+      flex-direction: column;
+      gap: 6px;
+      margin-bottom: 28px;
+    }
+    .rr-in-motion-line { font-size: 16px; }
+  }
+</style>

src/components/admin/RoadmapTab.astro

@@ -64,6 +64,7 @@ const grouped: Record<Status, RoadmapItemWithAttribution[]> = {
       <div class="field">
         <label for="description" class="label-sm field-label">Description</label>
         <textarea id="description" name="description" class="input body-md" rows="3">{editing?.description ?? ''}</textarea>
+        <span class="body-sm muted">For shipping items: the first sentence appears on /roadmap as the "In motion right now" line. Make it count.</span>
       </div>
 
       <div class="field">

src/pages/roadmap.astro

@@ -1,6 +1,7 @@
 ---
 import AppLayout from '../layouts/AppLayout.astro';
 import LatestDispatchBanner from '../components/LatestDispatchBanner.astro';
+import RoadmapInMotion from '../components/RoadmapInMotion.astro';
 import RoadmapRoute from '../components/RoadmapRoute.astro';
 import { getAllRoadmapItems } from '../lib/db';
 
@@ -18,13 +19,15 @@ const items = getAllRoadmapItems()
       <h1 class="page-title">What we are building.</h1>
       <p class="page-sub">
         A live picture of the work. What's in motion, what's queued,
-        what we're still thinking about. Hover any milestone for the
-        full story.
+        what we're still thinking about. Tap or hover any milestone
+        for the full story.
       </p>
     </header>
 
     <LatestDispatchBanner />
 
+    <RoadmapInMotion items={items} />
+
     <RoadmapRoute items={items} />
   </div>
 </AppLayout>
@@ -63,14 +66,14 @@ const items = getAllRoadmapItems()
     max-width: 540px;
   }
 
-  /* The banner already has its own bottom-margin via the layout in
-     the parent. Add the spec'd 56px below it before the route header. */
-  .page :global(.banner) { margin-bottom: 56px; }
+  /* In-motion strip lives between banner and route; banner margin
+     tightens to 40px because the strip carries its own 36px below. */
+  .page :global(.banner) { margin-bottom: 40px; }
 
   @media (max-width: 767px) {
     .page { padding: 32px 24px 64px; }
     .page-title { font-size: 36px; }
     .page-header { margin-bottom: 28px; }
-    .page :global(.banner) { margin-bottom: 36px; }
+    .page :global(.banner) { margin-bottom: 28px; }
   }
 </style>