Fix note UX: unreachable wiki link, white Save hover, stale icon preview, invisible new points

- "Nearby on Wikipedia" linked to KIWIX_URL, a Docker-internal hostname
  (http://kiwix:8080) no real browser can resolve. Split it: KIWIX_URL
  stays server-side-only for the reachability check, and the link
  itself is built from KIWIX_PUBLIC_PORT (kiwix-serve's newly
  published host port) plus whatever host the visitor already used to
  reach maptool — works regardless of which hostname/IP that is.
- The Save button went white on hover in GTK-themed Chrome: the
  browser's native button skin was painting over the custom
  background because appearance wasn't reset.
- The map preview marker for a pending note always showed a plain red
  pin no matter which icon was picked in the form. NoteSaveForm now
  reports icon changes via onIconChange so NotesControl can update the
  marker's glyph live.
- Saving a note (or a Measure "Save as note") left the new/grown
  .geojson file unchecked and invisible until manually toggled on.
  notifyGpxStoreChanged now carries the affected path so
  GpxPanelControl auto-shows it.

docker-compose.yaml

@@ -37,7 +37,14 @@ services:
       # actually being present: GET /api/kiwix pings it and just reports
       # unavailable if the container isn't up/reachable, same story as
       # every other optional-local-file feature (offline.pmtiles, etc).
+      # Server-side reachability check only — a browser on the LAN can't
+      # resolve this hostname, see KIWIX_PUBLIC_PORT below.
       KIWIX_URL: "http://kiwix:8080"
+      # The host port kiwix's own ports: mapping below publishes it on —
+      # app.rb builds the browser-facing "Nearby on Wikipedia" link from
+      # whatever host the visitor used to reach maptool itself plus this
+      # port, since KIWIX_URL above is Docker-internal only.
+      KIWIX_PUBLIC_PORT: "8090"
     volumes:
       # Uploaded GPX files and the offline PMTiles extract — kept outside
       # the image so a rebuild/redeploy doesn't wipe them (see
@@ -87,5 +94,10 @@ services:
     # passing it again produced "Unexpected argument: --port=8080,
     # --port=8080, /data/wikipedia.zim" and kiwix-serve refused to start.
     command: ["/data/wikipedia.zim"]
+    # Published so browsers on the LAN can reach kiwix-serve's own search
+    # UI directly (see maptool's KIWIX_PUBLIC_PORT above) — 8090, not 8080,
+    # since 8080 is already taken by another container on this host.
+    ports:
+      - "8090:8080"
     volumes:
       - ./data/kiwix/wikipedia.zim:/data/wikipedia.zim