Fix national_rates.json deployment — copy to public/ directory

- Add missing data/national_rates.json fixture (was only in src/data/, not served by Vite)
- LoadingAnimation.jsx: Use import.meta.env.BASE_URL for national rates path
- Ensures file is available at /crdc-demo/data/national_rates.json on git-pages

public/data/national_rates.json

@@ -0,0 +1,44 @@
+{
+  "metadata": {
+    "source": "CRDC School Arrest Rate API / Knowles & Miller 2025, White Paper §3 Data",
+    "year": "21-22",
+    "description": "National arrest rates per 1,000 students for each race×sex group in the 2021-22 CRDC. Generated from crdc_2122 with RACE != TOTAL and SEX != TOTAL: sum(ARRESTS) / (sum(stu_enroll)/1000).",
+    "note": "These are observed national rates, used for comparison in Charts 3 & 6."
+  },
+  "rates_per_1000": {
+    "WH_F": 0.34,
+    "WH_M": 0.67,
+    "BL_F": 1.25,
+    "BL_M": 1.98,
+    "HI_F": 0.42,
+    "HI_M": 0.88,
+    "AM_F": 0.91,
+    "AM_M": 1.40
+  },
+  "observed_arrests": {
+    "WH_F": 3653,
+    "WH_M": 7606,
+    "BL_F": 4420,
+    "BL_M": 7246,
+    "HI_F": 2876,
+    "HI_M": 6270,
+    "AM_F": 202,
+    "AM_M": 327
+  },
+  "enrollment": {
+    "WH_F": 10624313,
+    "WH_M": 11322741,
+    "BL_F": 3530162,
+    "BL_M": 3667523,
+    "HI_F": 6805008,
+    "HI_M": 7109091,
+    "AM_F": 222963,
+    "AM_M": 233442
+  },
+  "totals": {
+    "arrests": 34846,
+    "enrollment": 48596489,
+    "rate_per_1000": 0.72,
+    "districts_reporting_arrests_pct": 11.6
+  }
+}

src/components/LoadingAnimation.jsx

@@ -67,7 +67,7 @@ export default function LoadingAnimation({ district, state }) {
         )
 
         // ——— National rates (from static fixture, instant) ———
-        const nationalPromise = fetch('/data/national_rates.json')
+        const nationalPromise = fetch(import.meta.env.BASE_URL + 'data/national_rates.json')
           .then(r => r.json())
           .then(data => { /* cache for ChartPanel */ window.__NATIONAL_RATES__ = data })
           .catch(() => {})