v2: 3D globe on zoom-out (#223) + colored news-cluster zones (#224)

- useMapCore: MapLibre v5 globe projection in style spec (auto flat on zoom-in)
- EventClustersLayer: per-cluster color by dominant impact (green/red) or stable
  per-event hue; opacity/width scale with post_count; enabled by default
- MapView: clusterZonesEnabled state + search-bar toggle
(#222's 24h default + filter-follows-map-move already present in source)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/Map/EventClustersLayer.jsx

@@ -109,9 +109,50 @@ function smoothPolygon(points) {
   return result;
 }
 
+// #224: derive a stable, distinct color per cluster from its topical identity
+// (event_key / title / dominant subject). Two unrelated events (e.g. a war vs a
+// natural disaster) therefore render as two clearly different colored regions.
+// If the cluster carries an explicit market impact (green/red), honor it.
+function hashString(str) {
+  let h = 0;
+  const s = String(str || "");
+  for (let i = 0; i < s.length; i++) {
+    h = (h << 5) - h + s.charCodeAt(i);
+    h |= 0;
+  }
+  return Math.abs(h);
+}
+
+function dominantImpact(cluster) {
+  const posts = Array.isArray(cluster?.member_posts) ? cluster.member_posts : [];
+  let green = 0;
+  let red = 0;
+  for (const p of posts) {
+    const imp = (p?.impact || p?.asset_impact || "").toString().toLowerCase();
+    if (imp === "green" || imp === "positive" || imp === "bull") green++;
+    else if (imp === "red" || imp === "negative" || imp === "bear") red++;
+  }
+  const top = (cluster?.impact || "").toString().toLowerCase();
+  if (top === "green" || top === "positive") return "green";
+  if (top === "red" || top === "negative") return "red";
+  if (green === 0 && red === 0) return "";
+  return green >= red ? "green" : "red";
+}
+
+function clusterColor(cluster) {
+  const impact = dominantImpact(cluster);
+  if (impact === "green") return "#22c55e";
+  if (impact === "red") return "#ef4444";
+  // Distinct hue per topic/event so related news share one color region.
+  const seed = cluster?.event_key || cluster?.subject || cluster?.title || cluster?.id;
+  const hue = hashString(seed) % 360;
+  return `hsl(${hue}, 72%, 58%)`;
+}
+
 // Create organic "lake" shape from cluster member posts
 function clusterToPolygon(cluster) {
   const { id, title, post_count, member_posts, bounding_box } = cluster;
+  const color = clusterColor(cluster);
 
   // Get valid points from member posts
   let points = [];
@@ -183,6 +224,7 @@ function clusterToPolygon(cluster) {
       id,
       title,
       post_count,
+      color,
     },
     geometry: {
       type: "Polygon",
@@ -199,6 +241,7 @@ function clusterToPoint(cluster) {
       id: cluster.id,
       title: cluster.title?.slice(0, 35) + (cluster.title?.length > 35 ? "..." : "") || "Cluster",
       post_count: cluster.post_count,
+      color: clusterColor(cluster),
     },
     geometry: {
       type: "Point",
@@ -333,13 +376,14 @@ export default function EventClustersLayer({ map, enabled = true, onClusterClick
             "visibility": "none",
           },
           paint: {
-            "fill-color": [
+            // #224: color each region by its dominant subject/impact (per-cluster)
+            "fill-color": ["coalesce", ["get", "color"], "#60a5fa"],
+            "fill-opacity": [
               "interpolate", ["linear"], ["get", "post_count"],
-              2, "#60a5fa",   // lighter blue
-              5, "#a78bfa",   // softer purple
-              10, "#f472b6",  // softer pink
+              2, 0.22,
+              10, 0.34,
+              40, 0.45,
             ],
-            "fill-opacity": 0.35,
           },
         });
 
@@ -352,13 +396,13 @@ export default function EventClustersLayer({ map, enabled = true, onClusterClick
             "visibility": "none",
           },
           paint: {
-            "line-color": [
+            "line-color": ["coalesce", ["get", "color"], "#93c5fd"],
+            "line-width": [
               "interpolate", ["linear"], ["get", "post_count"],
-              2, "#93c5fd",   // even lighter for border
-              5, "#c4b5fd",
-              10, "#f9a8d4",
+              2, 1.5,
+              40, 3,
             ],
-            "line-width": 2,
+            "line-opacity": 0.85,
             "line-blur": 1,
           },
         });

src/components/Map/MapView.jsx

@@ -244,6 +244,22 @@ export default function MapView({
     }
   });
 
+  // #224: colored news-cluster zones on the map (default ON).
+  const CLUSTER_ZONES_KEY = "sociowire:clusterZones";
+  const [clusterZonesEnabled, setClusterZonesEnabled] = useState(() => {
+    try {
+      const saved = localStorage.getItem(CLUSTER_ZONES_KEY);
+      return saved === null ? true : saved === "true";
+    } catch {
+      return true;
+    }
+  });
+  useEffect(() => {
+    try {
+      localStorage.setItem(CLUSTER_ZONES_KEY, clusterZonesEnabled ? "true" : "false");
+    } catch {}
+  }, [clusterZonesEnabled]);
+
   const debugEnabled = (() => {
     try {
       return typeof window !== "undefined" &&
@@ -2122,7 +2138,7 @@ export default function MapView({
         {viewParams.center && (
           <EventClustersLayer
             map={mapRef.current}
-            enabled={contentFilter === "cluster"}
+            enabled={clusterZonesEnabled || contentFilter === "cluster"}
             onClusterPostIds={setClusterPostIds}
             onClusterClick={(cluster) => {
             // Pan to cluster and potentially show details
@@ -2228,6 +2244,15 @@ export default function MapView({
                 >
                   <i className="fa-solid fa-share-nodes"></i>
                 </button>
+                <button
+                  type="button"
+                  className={"sw-search__iconBtn" + (clusterZonesEnabled ? " is-active" : "")}
+                  title={clusterZonesEnabled ? "Hide news zones" : "Show news zones"}
+                  aria-pressed={clusterZonesEnabled}
+                  onClick={() => setClusterZonesEnabled((v) => !v)}
+                >
+                  <i className="fa-solid fa-layer-group"></i>
+                </button>
                 <button
                   type="button"
                   className="sw-search__iconBtn"

src/components/Map/useMapCore.js

@@ -23,6 +23,10 @@ function getBaseStyle(theme) {
 
   return {
     version: 8,
+    // #223: real 3D globe when zoomed out (MapLibre v5 globe projection
+    // auto-transitions to a flat mercator map as you zoom in). Declaring it in
+    // the style spec keeps it applied across theme changes (setStyle).
+    projection: { type: "globe" },
     sources: {
       "carto-base": {
         type: "raster",