fix: restore post-v1.1.14 features while preserving asset updates

Undo the full-tree rollback in 6ea1b3d and restore the pre-rollback v1.2.0 code. Preserve the new asset flow rules, abnormal inventory separation, range drilldowns and date picker; adapt the regression test to the restored routes layout.

vite.config.ts

@@ -1,15 +1,35 @@
-import { defineConfig } from 'vite';
+import { defineConfig, loadEnv } from 'vite';
 import react from '@vitejs/plugin-react';
 import tailwindcss from '@tailwindcss/vite';
+import { energyDevMockApi } from './src/modules/energy/hydrogen/dev-mock-api';
 
-export default defineConfig({
-  plugins: [react(), tailwindcss()],
-  server: {
-    proxy: {
-      '/api': {
-        target: 'http://localhost:3001',
-        changeOrigin: true,
+export default defineConfig(({ mode }) => {
+  const env = loadEnv(mode, process.cwd(), '');
+
+  return {
+    plugins: [
+      react(),
+      tailwindcss(),
+      ...(env.DEV_MOCK_API === '1' ? [energyDevMockApi()] : []),
+    ],
+    server: {
+      allowedHosts: ['biz.u2145933.nyat.app'],
+      proxy: {
+        '/api': {
+          target: 'http://localhost:3001',
+          changeOrigin: true,
+          configure(proxy) {
+            // A failed upstream BI aggregation must become an HTTP error for
+            // the UI fallback, never terminate the 8115 preview process.
+            proxy.on('error', (_error, _request, response) => {
+              if (response && 'writeHead' in response && !response.headersSent) {
+                response.writeHead(502, { 'Content-Type': 'text/plain; charset=utf-8' });
+                response.end('Upstream API temporarily unavailable');
+              }
+            });
+          },
+        },
       },
     },
-  },
+  };
 });