fix(storm-intel): call IEM API directly from browser — no proxy needed

IEM geojson/sbw.geojson has CORS open to all origins so the browser can
fetch it directly. Moves all transformation logic into useStormEvents.js,
eliminating the need for vercel dev or any server-side proxy. Works with
plain pnpm run dev on localhost. Falls back to MOCK_STORM_EVENTS if IEM
is unreachable. api/storm-polygons.js kept as optional edge cache layer.

src/hooks/useStormEvents.js

@@ -1,18 +1,121 @@
 /**
  * Storm events hook.
  *
- * USE_MOCK = true  → returns MOCK_STORM_EVENTS from mockStore (local dev)
+ * USE_MOCK = true  → returns MOCK_STORM_EVENTS (instant, no network)
- * USE_MOCK = false → calls /api/storm-events which proxies NWS/NOAA
+ * USE_MOCK = false → calls IEM SBW archive directly from the browser.
+ *                    IEM is a free public API (Iowa State University) with
+ *                    CORS open to all origins — no proxy needed, works on
+ *                    localhost and production identically.
+ *                    Falls back to MOCK_STORM_EVENTS if IEM is unreachable.
  */
 
 import { useState, useEffect, useMemo } from 'react';
 import { MOCK_STORM_EVENTS } from '../data/mockStore';
 
-// false = use real IEM/NWS data via /api/storm-polygons (falls back to mock if unreachable)
 const USE_MOCK = false;
 
-const DATE_RANGE_DAYS = { '1m': 30, '3m': 90, '6m': 180, '12m': 365, '18m': 548, '24m': 730, '36m': 1095 };
+// Iowa Environmental Mesonet — storm-based warnings archive
+const IEM_SBW  = 'https://mesonet.agron.iastate.edu/geojson/sbw.geojson';
+const WFO      = 'FWD'; // Fort Worth NWS office — covers Collin County / Plano TX
 
+// Plano / Collin County bounding box
+const BBOX = { minLat: 32.85, maxLat: 33.45, minLon: -97.15, maxLon: -96.35 };
+
+// Only keep storm-relevant phenomena
+const KEEP_PH = new Set(['SV', 'TO', 'FF']);
+
+function extractRing(geom) {
+    if (!geom) return null;
+    if (geom.type === 'Polygon'      && geom.coordinates?.[0]?.length >= 3)
+        return geom.coordinates[0];
+    if (geom.type === 'MultiPolygon' && geom.coordinates?.[0]?.[0]?.length >= 3)
+        return geom.coordinates[0][0];
+    return null;
+}
+
+function inBBox(rawCoords) {
+    return rawCoords.some(([lon, lat]) =>
+        lat >= BBOX.minLat && lat <= BBOX.maxLat &&
+        lon >= BBOX.minLon && lon <= BBOX.maxLon
+    );
+}
+
+function derivedAreaName(rawCoords, ph) {
+    const n         = rawCoords.length;
+    const centerLat = rawCoords.reduce((s, [, lat]) => s + lat, 0) / n;
+    const centerLon = rawCoords.reduce((s, [lon])   => s + lon, 0) / n;
+
+    let city;
+    if      (centerLat > 33.22)                        city = 'McKinney';
+    else if (centerLat > 33.16 && centerLon < -96.79)  city = 'Frisco';
+    else if (centerLat > 33.16)                        city = 'N. Plano / Allen';
+    else if (centerLat > 33.10)                        city = 'Allen';
+    else if (centerLon < -96.84)                       city = 'Legacy Corridor';
+    else if (centerLat > 33.04)                        city = 'Central Plano';
+    else                                               city = 'S. Plano';
+
+    const label = ph === 'TO' ? 'Tornado Warning'
+                : ph === 'FF' ? 'Flash Flood Warning'
+                : 'Severe Thunderstorm';
+    return `${city} — ${label}`;
+}
+
+function featureToEvent(feature, idx) {
+    const p  = feature.properties || {};
+    const ph = p.phenomena || '';
+    if (!KEEP_PH.has(ph)) return null;
+
+    const rawCoords = extractRing(feature.geometry);
+    if (!rawCoords || !inBBox(rawCoords)) return null;
+
+    const polygon = rawCoords.map(([lon, lat]) => [lat, lon]); // → Leaflet [lat,lon]
+
+    const type = ph === 'TO' ? 'tornado' : ph === 'FF' ? 'flood' : 'hail';
+
+    const hailIn = p.hailtag ? parseFloat(p.hailtag) : null;
+    const severity = ph === 'TO'    ? 'severe'
+        : hailIn !== null
+            ? (hailIn >= 2.0 ? 'severe' : hailIn >= 1.5 ? 'significant' : hailIn >= 1.0 ? 'moderate' : 'trace')
+        : ph === 'FF'   ? 'moderate'
+        : 'significant';
+
+    return {
+        id:             `IEM-${WFO}-${ph}-${p.year ?? ''}-${p.eventid ?? idx}`,
+        date:           p.issue || p.polygon_begin || new Date().toISOString(),
+        type,
+        severity,
+        maxHailSize:    hailIn,
+        areaName:       derivedAreaName(rawCoords, ph),
+        county:         'Collin',
+        estimatedHomes: null,
+        description:    `${type === 'tornado' ? 'Tornado Warning' : type === 'flood' ? 'Flash Flood Warning' : 'Severe Thunderstorm Warning'} — NWS ${WFO}`,
+        source:         'IEM/NWS',
+        polygon,
+    };
+}
+
+async function fetchIEMEvents() {
+    const now    = new Date();
+    const cutoff = new Date(now.getTime() - 36 * 30.44 * 86400000);
+    const url    = `${IEM_SBW}?sts=${encodeURIComponent(cutoff.toISOString())}&ets=${encodeURIComponent(now.toISOString())}&wfo=${WFO}`;
+
+    const res = await fetch(url);
+    if (!res.ok) throw new Error(`IEM ${res.status}`);
+
+    const geojson = await res.json();
+    const events  = (geojson.features || [])
+        .map((f, i) => featureToEvent(f, i))
+        .filter(Boolean)
+        .sort((a, b) => new Date(b.date) - new Date(a.date))
+        .slice(0, 150);
+
+    if (events.length === 0) throw new Error('no local events');
+    return events;
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+
+const DATE_RANGE_DAYS  = { '1m': 30, '3m': 90, '6m': 180, '12m': 365, '18m': 548, '24m': 730, '36m': 1095 };
 const SEVERITY_ORDER   = { severe: 4, significant: 3, moderate: 2, trace: 1 };
 
 export function useStormEvents({
@@ -40,14 +143,9 @@ export function useStormEvents({
                     data = MOCK_STORM_EVENTS;
                 } else {
                     try {
-                        // Always fetch full 36-month window so range changes are instant client-side.
+                        data = await fetchIEMEvents();
-                        // Falls back to MOCK_STORM_EVENTS when /api routes aren't available (local vite dev).
-                        const res = await fetch('/api/storm-polygons?months=36');
-                        if (!res.ok) throw new Error(`${res.status}`);
-                        const json = await res.json();
-                        if (!Array.isArray(json) || json.length === 0) throw new Error('empty');
-                        data = json;
                     } catch {
+                        // IEM unreachable or no local events — fall back to mock
                         data = MOCK_STORM_EVENTS;
                     }
                 }
@@ -61,7 +159,7 @@ export function useStormEvents({
 
         load();
         return () => { cancelled = true; };
-    // Run once — 36mo dataset is fetched in full; all filtering is client-side in useMemo below
+    // Fetch once — full 36mo dataset loaded; all filtering is client-side below
     // eslint-disable-next-line react-hooks/exhaustive-deps
     }, []);
 
@@ -69,7 +167,6 @@ export function useStormEvents({
         let filtered = allEvents.filter(e => {
             const d = new Date(e.date);
 
-            // Custom date range
             if (dateRange === 'custom') {
                 const start = customStart ? new Date(customStart) : new Date(0);
                 const end   = customEnd   ? new Date(customEnd + 'T23:59:59') : new Date();

vercel.json

@@ -1,6 +1,9 @@
 {
+  "buildCommand": "pnpm build",
+  "devCommand": "pnpm dev",
+  "outputDirectory": "dist",
   "rewrites": [
-    { "source": "/api/(.*)", "destination": "/api/$1" },
+    { "source": "/((?!api/).*)", "destination": "/index.html" }
-    { "source": "/(.*)", "destination": "/index.html" }
   ]
 }
+