Format the structured lines in park4night waypoint popups

A park4night <desc> packs a free-text narrative and several lines of
structured data (address, rating, services, activities, the listing URL)
into one field, separated only by newlines. Rendered as a single paragraph
it read as a wall of run-together text — no visual hierarchy between the
actual description and what's really key-value metadata.

formatDescription now recognizes "Label: value" lines (Rating/Services/
Activities) and bare-URL lines, and gives each its own row instead of
burying them in the narrative paragraph: a bordered meta block with bold
labels, and an isolated link line. Anything that doesn't match — the real
narrative text, or a plain GPX file's <desc> with no such structure — stays
exactly as it rendered before, so this only adds structure, never removes
or reorders text.

public/js/gpx.js

@@ -757,7 +757,7 @@ function popupHtml({ name, description, time, category }) {
   const parts = [];
   if (name) parts.push(`<strong>${escapeHtml(name)}</strong>`);
   if (category) parts.push(`<p class="gpx-popup__category">${escapeHtml(category)}</p>`);
-  if (description) parts.push(`<p>${linkify(description).replace(/\n/g, "<br>")}</p>`);
+  if (description) parts.push(formatDescription(description));
   if (time) {
     const parsed = new Date(time);
     if (!Number.isNaN(parsed.getTime())) {
@@ -795,6 +795,52 @@ function escapeHtml(text) {
   return div.innerHTML;
 }
 
+// park4night exports pack a free-text description and several lines of
+// structured data (address, rating, services, activities, the listing URL)
+// into one <desc> blob, separated only by newlines — rendered as one plain
+// paragraph, it read as a wall of run-together text. Lines matching a
+// recognizable "Label: value" or bare-URL shape get pulled out and rendered
+// as their own visually distinct rows instead; anything else (the actual
+// narrative, or a plain GPX file's <desc> with no such structure at all)
+// stays exactly as before, one paragraph with line breaks — so this only
+// ever adds structure, never loses any text.
+const DESCRIPTION_META_LINE = /^(Rating|Services|Activities):\s*(.+)$/i;
+const DESCRIPTION_LINK_LINE = /^https?:\/\/\S+$/;
+
+function formatDescription(description) {
+  const body = [];
+  const meta = [];
+  const links = [];
+
+  for (const line of description.split("\n")) {
+    const trimmed = line.trim();
+    const metaMatch = trimmed.match(DESCRIPTION_META_LINE);
+    if (DESCRIPTION_LINK_LINE.test(trimmed)) {
+      links.push(trimmed);
+    } else if (metaMatch) {
+      meta.push(metaMatch);
+    } else {
+      body.push(line);
+    }
+  }
+
+  const parts = [];
+  const bodyText = body.join("\n").trim();
+  if (bodyText) parts.push(`<p class="gpx-popup__description">${linkify(bodyText).replace(/\n/g, "<br>")}</p>`);
+  if (meta.length > 0) {
+    const rows = meta
+      .map(
+        ([, label, value]) =>
+          `<div class="gpx-popup__meta-row"><span class="gpx-popup__meta-label">${escapeHtml(label)}</span> ${escapeHtml(value)}</div>`,
+      )
+      .join("");
+    parts.push(`<div class="gpx-popup__meta">${rows}</div>`);
+  }
+  links.forEach((url) => parts.push(`<p class="gpx-popup__link">${urlToLink(url)}</p>`));
+
+  return parts.join("");
+}
+
 // Turns bare URLs in untrusted text into safe <a> links: the string is
 // split on the URL pattern and every piece is escaped — including the URL
 // itself, both as href and as link text — before any HTML is assembled, so