feat(energy): add module shell, register in nav

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/modules/energy/TrendBadge.tsx

@@ -0,0 +1,24 @@
+import { ArrowUp, ArrowDown, Minus } from 'lucide-react';
+
+export interface TrendBadgeProps {
+  value: number;          // -1..+1, 0 表示持平
+  className?: string;
+}
+
+export default function TrendBadge({ value, className = '' }: TrendBadgeProps) {
+  const isUp = value > 0.0001;
+  const isDown = value < -0.0001;
+  const cls = isUp
+    ? 'bg-emerald-50 text-emerald-600'
+    : isDown
+      ? 'bg-red-50 text-red-600'
+      : 'bg-slate-100 text-slate-500';
+  const Icon = isUp ? ArrowUp : isDown ? ArrowDown : Minus;
+  const sign = isUp ? '+' : '';
+  return (
+    <span className={`inline-flex items-center gap-0.5 rounded-full px-2 py-0.5 text-[11px] font-bold ${cls} ${className}`}>
+      <Icon size={11} />
+      {sign}{(value * 100).toFixed(2)}%
+    </span>
+  );
+}