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.

docs/architecture.adoc

@@ -315,7 +315,7 @@ Like the radar overlay, GPX layers are removed by `map.setStyle()`
 (switching Online/Offline) and get re-added on `style.load` for
 whichever files were checked.
 
-Waypoint popups:: Clicking a waypoint circle opens a MapLibre popup
+Waypoint popups:: Clicking a waypoint badge opens a MapLibre popup
 with its name, category (if any), description and time. Click/hover handling is
 registered once per file (via `map.on(type, layerId, handler)`, a
 delegated listener that survives `setStyle()`) rather than on every
@@ -328,6 +328,20 @@ splitting the text on a URL pattern and escaping every piece
 assembling any HTML; the URL pattern excludes quote characters, so a
 matched URL can never break out of the `href="..."` attribute. Every
 other value is HTML-escaped before being handed to `Popup#setHTML`.
++
+A park4night `<desc>` packs a free-text narrative and several lines of
+structured data (address, rating, services, activities, the listing
+URL) into that one field, separated only by newlines — rendered as a
+single paragraph, it read as a wall of run-together text.
+`formatDescription` pulls out whichever lines match a recognizable
+`Label: value` shape (`Rating`/`Services`/`Activities`) or are a bare
+URL, and renders each kind with its own visual treatment (a bordered
+"meta" block with bold labels for the former, an isolated link line for
+the latter); everything else — the actual narrative, or a plain GPX
+file's `<desc>` with none of this structure at all — renders exactly as
+before, one paragraph with line breaks. So this only ever adds
+structure on top of recognized lines; it never loses or hides text from
+files that don't have any.
 
 Track properties:: Every track feature (both formats) also carries
 `distance_meters`, `elevation_gain_meters`, `duration_secs`,