deps: react-leaflet 1.8 -> 4.2 (+ leaflet 1.9) — the last legacy react-* lib

Ground-up hooks rewrite of the app's core map. Removes the final batch of
React-19-blocking warnings (legacy context on Map/LayersControl/TileLayer/
Marker/CircleMarker/Circle/Tooltip + ReactDOM.render from the old controls).

Core: <Map> -> <MapContainer>; .leafletElement refs (6 files) -> the map/
layer instances directly, via a <MapReady> child (useMap) + plain refs on
Marker/Circle/GeoJSON; controlled viewport (onViewportChanged + state.center/
zoom) -> <MapEvents> (useMapEvents moveend/zoomend) + imperative setView;
onClick -> eventHandlers={{click}}; Path styling -> pathOptions/style;
subsUnion takes the L.Map directly.

The 4 v1-only plugins reimplemented (new in-repo helpers under Maps/):
- react-leaflet-control -> MapControl (L.Control + createPortal)
- react-leaflet-google  -> GoogleMutantLayer (createLayerComponent +
  leaflet.gridlayer.googlemutant; Google Maps API already loaded by Gkeys)
- react-leaflet-fullscreen -> createControlComponent + leaflet.fullscreen
- leaflet-sleep / leaflet-graphicscale kept as vanilla (work on leaflet 1.9)

Browser-verified: /fires (tiles, OSM+Google layer switch, custom control,
fullscreen, graphic scale, pan/zoom -> re-fetch, no NaN), fire detail
(GeoJSON rect + fitBounds), home (3 maps coexist; SelectionMap draggable
marker -> updatePosition + distance circle). Console now shows 0 React
warnings on home/fires. REST smoke byte-identical.

imports/ui/pages/Fires/Fires.js

@@ -10,7 +10,8 @@ import { Row, Col, Alert, Form } from 'react-bootstrap';
 import { Meteor } from 'meteor/meteor';
 import { Bert } from 'meteor/themeteorchef:bert';
 import { Helmet } from 'react-helmet-async';
-import { Map, GeoJSON } from 'react-leaflet';
+import { MapContainer, GeoJSON } from 'react-leaflet';
+import { MapReady } from '/imports/ui/components/Maps/MapBridge';
 import { rectangleAround } from 'map-common-utils';
 import DefMapLayers from '/imports/ui/components/Maps/DefMapLayers';
 import NotFound from '/imports/ui/pages/NotFound/NotFound';
@@ -75,9 +76,15 @@ class Fire extends React.Component {
     });
   }
 
-  handleLeafletMapLoad(map) {
-    if (map && map.leafletElement) {
-      const lmap = map.leafletElement;
+  // v4: MapReady hands us the ready Leaflet map directly (no ref/.leafletElement)
+  handleMapReady(lmap) {
+    this.fireMap = lmap;
+    this.handleLeafletMapLoad(lmap);
+    if (this.circle) lmap.fitBounds(this.circle.getBounds());
+  }
+
+  handleLeafletMapLoad(lmap) {
+    if (lmap) {
       const bounds = lmap.getBounds();
       const ne = bounds.getNorthEast();
       const sw = bounds.getSouthWest();
@@ -103,8 +110,9 @@ class Fire extends React.Component {
   }
 
   handleLeafletCircleLoad(circle) {
-    if (this.fireMap && this.fireMap.leafletElement && circle && circle.leafletElement) {
-      this.fireMap.leafletElement.fitBounds(circle.leafletElement.getBounds());
+    // v4: circle is the Leaflet GeoJSON layer; this.fireMap is the Leaflet map
+    if (this.fireMap && circle) {
+      this.fireMap.fitBounds(circle.getBounds());
     }
   }
 
@@ -134,27 +142,17 @@ class Fire extends React.Component {
         {!loading &&
          <Fragment>
            <h4 className="page-header">{this.title}</h4>
-           <Map
-               ref={(map) => {
-                   this.fireMap = map;
-                   this.handleLeafletMapLoad(map);
-                 }}
-               animate
-               sleep={false}
+           <MapContainer
                center={[fire.lat, fire.lon]}
                className="fire-leaflet-container"
                zoom={13}
            >
-             <Fragment>
-               <GeoJSON
-                   ref={(circle) => { this.circle = circle; this.handleLeafletCircleLoad(circle); }}
-                   data={rect}
-                   color="red"
-                   stroke
-                   width="1"
-                   fillOpacity="0.0"
-               />
-             </Fragment>
+             <MapReady onReady={map => this.handleMapReady(map)} />
+             <GeoJSON
+                 ref={(circle) => { this.circle = circle; this.handleLeafletCircleLoad(circle); }}
+                 data={rect}
+                 style={{ color: 'red', stroke: true, weight: 1, fillOpacity: 0 }}
+             />
              <FireList
                  t={t}
                  history={this.props.history}
@@ -179,7 +177,7 @@ class Fire extends React.Component {
              />
              <DefMapLayers satellite />
              <FullScreenMap />
-           </Map>
+           </MapContainer>
            <p>{t('Coordenadas:')} {fire.lat}, {fire.lon}</p>
            {(fire.type === 'modis' || fire.type === 'viirs') &&
             <Fragment>