Split notes into a title + body, with light self-authored markdown

Both NoteSaveForm (create) and the popup's inline Edit form now have
a title input (-> properties.name, shown in the black header, same as
every other waypoint popup) and a separate body textarea (->
properties.description) for more detail than a single line.

New formatNoteBody renders that body with a small self-rolled
markdown subset — **bold**, *italic*, auto-linked URLs (reusing the
existing linkify), newlines to <br> — deliberately a new function, not
a change to formatDescription: that one renders uploaded GPX/park4night
content, which is untrusted, and docs/nps-resources.adoc already has a
specific call not to add markdown rendering to that path. A note's
body is written by the logged-in viewer themselves, not uploaded, so
that concern doesn't apply here — the escape-then-selectively-markup
order (linkify first, since it does its own escaping, then wrap
already-escaped text in real <strong>/<em> tags) keeps it safe either
way.

Verified live: title renders in the popup header, **bold**/*italic*/
a URL in the body all render correctly. Full test suite: 115 runs, 0
failures (unaffected — description is just another property, not
something the backend routes inspect).

public/js/notes.js

@@ -28,7 +28,8 @@ export class NoteSaveForm {
     this._el.className = "notes-panel__form";
     this._el.hidden = true;
     this._el.innerHTML = `
-      <textarea class="notes-panel__text" rows="2" placeholder="Note…"></textarea>
+      <input type="text" class="notes-panel__title" placeholder="Title">
+      <textarea class="notes-panel__body" rows="3" placeholder="Details (optional) — **bold**, *italic*, links"></textarea>
       <select class="notes-panel__target"></select>
       <input type="text" class="notes-panel__new-name" placeholder="Layer name" hidden>
       <div class="notes-panel__actions">
@@ -38,7 +39,8 @@ export class NoteSaveForm {
     `;
     container.appendChild(this._el);
 
-    this._text = this._el.querySelector(".notes-panel__text");
+    this._title = this._el.querySelector(".notes-panel__title");
+    this._body = this._el.querySelector(".notes-panel__body");
     this._target = this._el.querySelector(".notes-panel__target");
     this._newName = this._el.querySelector(".notes-panel__new-name");
     this._saveButton = this._el.querySelector(".notes-panel__save");
@@ -58,8 +60,9 @@ export class NoteSaveForm {
   async open(geometry) {
     this._geometry = geometry;
     this._el.hidden = false;
-    this._text.value = "";
-    this._text.focus();
+    this._title.value = "";
+    this._body.value = "";
+    this._title.focus();
     await this._populateTargets();
   }
 
@@ -90,8 +93,9 @@ export class NoteSaveForm {
   }
 
   async _save() {
-    const text = this._text.value.trim();
-    if (!text || !this._geometry) return;
+    const title = this._title.value.trim();
+    const details = this._body.value.trim();
+    if (!title || !this._geometry) return;
 
     const isNewLayer = this._target.value === NEW_LAYER_VALUE;
     const name = isNewLayer ? this._newName.value.trim() : "";
@@ -102,17 +106,23 @@ export class NoteSaveForm {
 
     const feature = {
       type: "Feature",
-      properties: { id: generateNoteId(), name: text, category: "Note", time: new Date().toISOString() },
+      properties: {
+        id: generateNoteId(),
+        name: title,
+        category: "Note",
+        time: new Date().toISOString(),
+        ...(details ? { description: details } : {}),
+      },
       geometry: this._geometry,
     };
 
-    const body = new URLSearchParams({ feature: JSON.stringify(feature) });
-    if (isNewLayer) body.set("name", name);
-    else body.set("path", this._target.value);
+    const requestBody = new URLSearchParams({ feature: JSON.stringify(feature) });
+    if (isNewLayer) requestBody.set("name", name);
+    else requestBody.set("path", this._target.value);
 
     this._saveButton.disabled = true;
     try {
-      const response = await fetch("/api/gpx/notes", { method: "POST", body });
+      const response = await fetch("/api/gpx/notes", { method: "POST", body: requestBody });
       if (!response.ok) throw new Error(`save failed: ${response.status}`);
       notifyGpxStoreChanged();
       this.close();