fix(spp_gis): make MapTiler API key optional with OSM tile fallback

When no MapTiler API key is configured, the map widget now falls back
to OpenStreetMap raster tiles instead of failing silently. This makes
the GIS features work out of the box without requiring a third-party
API key. Users who want vector tiles can still configure a MapTiler key.

Author: jeremi

spp_gis/static/src/js/widgets/gis_edit_map/field_gis_edit_map.esm.js

@@ -32,7 +32,9 @@ export class FieldGisEditMap extends Component {
         });
 
         onMounted(async () => {
-            maptilersdk.config.apiKey = this.mapTilerKey;
+            if (this.mapTilerKey) {
+                maptilersdk.config.apiKey = this.mapTilerKey;
+            }
             const editInfo = await this.orm.call(
                 this.props.record.resModel,
                 "get_edit_info_for_gis_column",
@@ -67,11 +69,9 @@ export class FieldGisEditMap extends Component {
             if (response.mapTilerKey) {
                 this.mapTilerKey = response.mapTilerKey;
                 this.webBaseUrl = response.webBaseUrl;
-            } else {
-                console.log("Error: Api Key not found.");
             }
         } catch (error) {
-            console.error("Error fetching environment variable:", error);
+            console.warn("Could not fetch MapTiler API key:", error);
         }
     }
 
@@ -86,6 +86,34 @@ export class FieldGisEditMap extends Component {
         }
     }
 
+    _getMapStyle() {
+        if (this.mapTilerKey) {
+            return maptilersdk.MapStyle.STREETS;
+        }
+        // Fallback: OSM raster tiles (no API key required)
+        return {
+            version: 8,
+            sources: {
+                osm: {
+                    type: "raster",
+                    tiles: ["https://tile.openstreetmap.org/{z}/{x}/{y}.png"],
+                    tileSize: 256,
+                    attribution:
+                        '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors',
+                },
+            },
+            layers: [
+                {
+                    id: "osm-tiles",
+                    type: "raster",
+                    source: "osm",
+                    minzoom: 0,
+                    maxzoom: 19,
+                },
+            ],
+        };
+    }
+
     renderMap() {
         if (this.props.record.data[this.props.name]) {
             const obj = JSON.parse(this.props.record.data[this.props.name]);
@@ -106,7 +134,7 @@ export class FieldGisEditMap extends Component {
 
         this.map = new maptilersdk.Map({
             container: this.id,
-            style: maptilersdk.MapStyle.STREETS,
+            style: this._getMapStyle(),
             center: this.defaultCenter,
             zoom: this.defaultZoom,
         });