Radar: switch to RainViewer (IEM blocks heavy tile use), cleaner Map tab

- /api/radar/times serves RainViewer frames (cached 2 min), IEM NEXRAD only as fallback;
  sources honour maxNativeZoom so tiles overzoom instead of going blank
- Map tab opens with radar + location dot only; wind/AQI/alerts/temp/sun/lightning are opt-in,
  readout chips follow their toggles
- Bolder location dot
- Satellite (GIBS) layer: new storage key, never persisted by storm taps, radar always draws above it

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

app/server.js

@@ -909,12 +909,38 @@ app.get('/api/alerts', async (req, res) => {
   }
 });
 
-// Radar/satellite tile configuration
+// Radar tile configuration.
+// Primary: RainViewer (global composite, 10-min frames, free, tiles load straight from their CDN).
+// Fallback: IEM NEXRAD (US only). IEM blocks IPs that pull too many tiles and answers with a "sorry"
+// redirect, so it must not be the only source. Satellite imagery is separate (NASA GIBS, client-side).
+let rainviewerCache = { at: 0, data: null };
+async function rainviewerFrames() {
+  if (rainviewerCache.data && Date.now() - rainviewerCache.at < 120000) return rainviewerCache.data;
+  const r = await fetchWithRetry('https://api.rainviewer.com/public/weather-maps.json', { attempts: 2, timeoutMs: 8000 });
+  if (!r.ok) throw new Error(`RainViewer ${r.status}`);
+  const j = await r.json();
+  const host = j.host || 'https://tilecache.rainviewer.com';
+  const frames = (j.radar?.past || []).slice(-12).map(f => ({
+    time: f.time,
+    url: `${host}${f.path}/256/{z}/{x}/{y}/2/1_1.png`, // colour scheme 2, smoothed, snow shown
+    isForecast: false,
+    maxNativeZoom: 7, // RainViewer's free tiles stop at z7; MapLibre overzooms beyond that
+  }));
+  if (!frames.length) throw new Error('RainViewer returned no frames');
+  rainviewerCache = { at: Date.now(), data: frames };
+  return frames;
+}
+
 app.get('/api/radar/times', async (req, res) => {
   try {
-    const now = Math.floor(Date.now() / 1000);
+    try {
+      const past = await rainviewerFrames();
+      return res.json({ provider: 'rainviewer', radar: { past }, satellite: { infrared: [] } });
+    } catch (e) {
+      console.error('RainViewer unavailable, falling back to IEM:', e.message);
+    }
 
-    // IEM NEXRAD tile service (US radar, public/free) with historical offsets for animation.
+    const now = Math.floor(Date.now() / 1000);
     const radarLayerBase = 'https://mesonet.agron.iastate.edu/cache/tile.py/1.0.0';
     const radarOffsetsMin = [55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 0];
     const radarPast = radarOffsetsMin.map(offset => {
@@ -926,28 +952,7 @@ app.get('/api/radar/times', async (req, res) => {
         maxNativeZoom: 12,
       };
     });
-
-    // IEM GOES East cloud/satellite frames for animation.
-    const satOffsetsMin = [30, 25, 20, 15, 10, 5, 0];
-    const satelliteInfrared = satOffsetsMin.map(offset => {
-      const layer = offset === 0 ? 'goes_east' : `goes_east_m${String(offset).padStart(2, '0')}m`;
-      return {
-        time: now - (offset * 60),
-        url: `https://mesonet.agron.iastate.edu/cache/tile.py/1.0.0/${layer}/{z}/{x}/{y}.png`,
-        isForecast: false,
-        maxNativeZoom: 10,
-      };
-    });
-
-    res.json({
-      provider: 'iem-radar-sat',
-      radar: {
-        past: radarPast,
-      },
-      satellite: {
-        infrared: satelliteInfrared,
-      },
-    });
+    res.json({ provider: 'iem-radar', radar: { past: radarPast }, satellite: { infrared: [] } });
   } catch (e) {
     console.error('Radar config error:', e.message);
     res.status(500).json({ error: 'Radar times failed' });