fix(storm-intel): hailIn TDZ crash, restore 36mo fetch, Go button for radius

- Fix ReferenceError: hailIn was used before declaration in featureToEvent,
  causing every SV event to throw and fall back to empty mock data
- Restore IEM fetch window to 36 months so events are available for all range chips
- Radius input now has explicit Go button (Enter key also applies); draft value
  shows hint until applied so accidental keystrokes don't retrigger search

src/hooks/useStormEvents.js

@@ -70,14 +70,14 @@ function featureToEvent(feature, idx) {
 
     const polygon = rawCoords.map(([lon, lat]) => [lat, lon]); // → Leaflet [lat,lon]
 
+    const hailIn = p.hailtag ? parseFloat(p.hailtag) : null;
+
     const type = ph === 'TO'                        ? 'tornado'
                : ph === 'FF'                        ? 'flood'
                : ph === 'WS' || ph === 'BZ'         ? 'snow'
                : ph === 'WW' || ph === 'IS'         ? 'ice'
                : hailIn !== null                    ? 'hail'
                : 'wind';
-
-    const hailIn = p.hailtag ? parseFloat(p.hailtag) : null;
     const severity = ph === 'TO'    ? 'severe'
         : hailIn !== null
             ? (hailIn >= 2.0 ? 'severe' : hailIn >= 1.5 ? 'significant' : hailIn >= 1.0 ? 'moderate' : 'trace')
@@ -101,7 +101,7 @@ function featureToEvent(feature, idx) {
 
 async function fetchIEMEvents() {
     const now    = new Date();
-    const cutoff = new Date(now.getTime() - 6 * 30.44 * 86400000);
+    const cutoff = new Date(now.getTime() - 36 * 30.44 * 86400000);
     const url    = `${IEM_SBW}?sts=${encodeURIComponent(cutoff.toISOString())}&ets=${encodeURIComponent(now.toISOString())}&wfo=${WFO}`;
 
     const res = await fetch(url);