fix(map): make idle GeoJSON dropzone non-interactive; remove dead code

- Idle dropzone was absolute inset-0 z-20 with no pointer-events-none,
  covering the MapLibre canvas and swallowing pan/zoom/draw events.
  Now pointer-events-none when idle, pointer-events-auto only during drag.
- Remove unused overlaysRef (written, never read).
- Remove unused GeoJsonData export and overlayHidden message (never rendered),
  keeping en/es/pt i18n in sync.

Author: github-actions[bot]

src/i18n/messages/en.json

@@ -1274,9 +1274,6 @@
   "map.overlay.empty": {
     "defaultMessage": "No reference layers added"
   },
-  "map.overlay.hidden": {
-    "defaultMessage": "Hidden"
-  },
   "map.overlay.invalid": {
     "defaultMessage": "Could not read “{name}”. Not valid GeoJSON."
   },

src/i18n/messages/es.json

@@ -393,7 +393,6 @@
   "map.overlay.drop": "Suelte un archivo .geojson para mostrarlo como capa de referencia",
   "map.overlay.dropActive": "Suelte el archivo para añadir la capa",
   "map.overlay.empty": "No hay capas de referencia añadidas",
-  "map.overlay.hidden": "Oculto",
   "map.overlay.invalid": "No se pudo leer “{name}”. GeoJSON no válido.",
   "map.overlay.remove": "Quitar capa",
   "map.overlay.title": "Capas de referencia",

src/i18n/messages/pt.json

@@ -393,7 +393,6 @@
   "map.overlay.drop": "Solte um arquivo .geojson para mostrá-lo como camada de referência",
   "map.overlay.dropActive": "Solte o arquivo para adicionar a camada",
   "map.overlay.empty": "Nenhuma camada de referência adicionada",
-  "map.overlay.hidden": "Oculto",
   "map.overlay.invalid": "Não foi possível ler “{name}”. GeoJSON inválido.",
   "map.overlay.remove": "Remover camada",
   "map.overlay.title": "Camadas de referência",

src/screens/MapScreen/GeoJsonOverlay.tsx

@@ -97,11 +97,7 @@ export function GeoJsonOverlay({ onOverlaysChange }: GeoJsonOverlayProps) {
   const dragDepthRef = useRef(0);
 
   // Sync overlay state up to the parent for map-layer rendering.
-  // Keep a ref of the latest value so the cleanup effect can notify
-  // the parent of the final empty state on unmount.
-  const overlaysRef = useRef(overlays);
   useEffect(() => {
-    overlaysRef.current = overlays;
     onOverlaysChange(overlays);
   }, [overlays, onOverlaysChange]);
 
@@ -223,8 +219,8 @@ export function GeoJsonOverlay({ onOverlaysChange }: GeoJsonOverlayProps) {
         onDrop={handleDrop}
         className={
           isDragActive
-            ? 'absolute inset-0 z-20 flex items-center justify-center border-4 border-dashed border-primary bg-primary/10'
-            : 'absolute inset-0 z-20'
+            ? 'absolute inset-0 z-20 pointer-events-auto flex items-center justify-center border-4 border-dashed border-primary bg-primary/10'
+            : 'absolute inset-0 z-20 pointer-events-none'
         }
         aria-label={intl.formatMessage(mapMessages.overlayDrop)}
       >
@@ -373,4 +369,3 @@ export function GeoJsonOverlay({ onOverlaysChange }: GeoJsonOverlayProps) {
 }
 
 export type { GeoJsonOverlayProps };
-export type { GeoJSON as GeoJsonData } from 'geojson';

src/screens/MapScreen/messages.ts

@@ -435,10 +435,6 @@ export const mapMessages = defineMessages({
     id: 'map.overlay.empty',
     defaultMessage: 'No reference layers added',
   },
-  overlayHidden: {
-    id: 'map.overlay.hidden',
-    defaultMessage: 'Hidden',
-  },
   // ── Cross-project map scope (#16) ────────────────────────────────────
   scopeThisProject: {
     id: 'map.scope.thisProject',