feat(storm-intel): richer event data + NWS boundary label in drawer and map tooltip

useStormEvents:
- Extract windSpeed (windtag), expireTime, warningDurationMins, phenomenaCode/Label
- Calculate polygonAreaSqMi via shoelace formula; estimate homes at 1800/sq mi

StormDetailDrawer — new sections:
- Weather Metrics: hail size with damage descriptor, wind speed with severity label
- Impact Zone: warning area sq miles + estimated homes in zone
- Warning Timeline: issued time, expired time, duration, issuing NWS office
- NWS Boundary note: explains the shape is a meteorologist-drawn warning zone

Map tooltip:
- Shows phenomenaLabel, wind speed, area sq mi
- Footer section labeled "NWS Warning Boundary" with shape explanation

src/hooks/useStormEvents.js

@@ -60,6 +60,32 @@ function derivedAreaName(rawCoords, ph) {
     return `${city} — ${label}`;
 }
 
+// Shoelace formula — polygon is Leaflet [lat,lon] pairs
+function polygonAreaSqMi(polygon) {
+    const n = polygon.length;
+    if (n < 3) return 0;
+    const avgLat = polygon.reduce((s, p) => s + p[0], 0) / n;
+    const mLat = 69.0;
+    const mLon = 69.0 * Math.cos(avgLat * Math.PI / 180);
+    let area = 0;
+    for (let i = 0; i < n; i++) {
+        const [lat1, lon1] = polygon[i];
+        const [lat2, lon2] = polygon[(i + 1) % n];
+        area += (lon1 * mLon) * (lat2 * mLat) - (lon2 * mLon) * (lat1 * mLat);
+    }
+    return Math.abs(area) / 2;
+}
+
+const PH_LABEL = {
+    SV: 'Severe Thunderstorm Warning',
+    TO: 'Tornado Warning',
+    FF: 'Flash Flood Warning',
+    WS: 'Winter Storm Warning',
+    BZ: 'Blizzard Warning',
+    WW: 'Winter Weather Advisory',
+    IS: 'Ice Storm Warning',
+};
+
 function featureToEvent(feature, idx) {
     const p  = feature.properties || {};
     const ph = p.phenomena || '';
@@ -70,7 +96,18 @@ function featureToEvent(feature, idx) {
 
     const polygon = rawCoords.map(([lon, lat]) => [lat, lon]); // → Leaflet [lat,lon]
 
-    const hailIn = p.hailtag ? parseFloat(p.hailtag) : null;
+    const hailIn    = p.hailtag  ? parseFloat(p.hailtag)  : null;
+    const windMph   = p.windtag  ? parseInt(p.windtag, 10) : null;
+    const issueTime = p.issue    || p.polygon_begin        || null;
+    const expireTime = p.expire  || p.polygon_end          || null;
+
+    const warningDurationMins = (issueTime && expireTime)
+        ? Math.round((new Date(expireTime) - new Date(issueTime)) / 60000)
+        : null;
+
+    const areaSqMi     = Math.round(polygonAreaSqMi(polygon));
+    // Suburban DFW density ~1 800 homes/sq mi — conservative (polygons often include open land)
+    const estHomes     = Math.round(areaSqMi * 1800);
 
     const type = ph === 'TO'                        ? 'tornado'
                : ph === 'FF'                        ? 'flood'
@@ -78,6 +115,7 @@ function featureToEvent(feature, idx) {
                : ph === 'WW' || ph === 'IS'         ? 'ice'
                : hailIn !== null                    ? 'hail'
                : 'wind';
+
     const severity = ph === 'TO'    ? 'severe'
         : hailIn !== null
             ? (hailIn >= 2.0 ? 'severe' : hailIn >= 1.5 ? 'significant' : hailIn >= 1.0 ? 'moderate' : 'trace')
@@ -85,16 +123,23 @@ function featureToEvent(feature, idx) {
         : 'significant';
 
     return {
-        id:             `IEM-${WFO}-${ph}-${p.year ?? ''}-${p.eventid ?? idx}`,
-        date:           p.issue || p.polygon_begin || new Date().toISOString(),
+        id:                   `IEM-${WFO}-${ph}-${p.year ?? ''}-${p.eventid ?? idx}`,
+        date:                 issueTime || new Date().toISOString(),
+        expireTime,
+        warningDurationMins,
         type,
         severity,
-        maxHailSize:    hailIn,
-        areaName:       derivedAreaName(rawCoords, ph),
-        county:         'Collin',
-        estimatedHomes: null,
-        description:    `${type === 'tornado' ? 'Tornado Warning' : type === 'flood' ? 'Flash Flood Warning' : 'Severe Thunderstorm Warning'} — NWS ${WFO}`,
-        source:         'IEM/NWS',
+        phenomenaCode:        ph,
+        phenomenaLabel:       PH_LABEL[ph] ?? ph,
+        maxHailSize:          hailIn,
+        windSpeed:            windMph,
+        areaName:             derivedAreaName(rawCoords, ph),
+        county:               'Collin',
+        areaSqMi,
+        estimatedHomes:       estHomes > 0 ? estHomes : null,
+        description:          `${PH_LABEL[ph] ?? ph} — NWS ${WFO}`,
+        source:               'IEM/NWS',
+        wfo:                  WFO,
         polygon,
     };
 }