feat: customer frontend, Sungrow collector fixes, real data (v1.2.0)

- Add frontend/ at root (no Three.js, no Charging, green #52c41a theme)
- Fix Sungrow collector: add curPage/size params, unit conversion
- Fix station-level dedup to prevent double-counting
- Add shared token cache for API rate limit protection
- Add .githooks/pre-commit, CLAUDE.md, .gitignore
- Update docker-compose.override.yml frontend -> ./frontend
- Pin bcrypt in requirements.txt
- Add BUYOFF_RESULTS_2026-04-05.md (39/43 pass)
- Data accuracy: 0.0% diff vs iSolarCloud

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/Dashboard/components/EnergyFlow.tsx

@@ -0,0 +1,96 @@
+import ReactECharts from 'echarts-for-react';
+import { useEffect, useState } from 'react';
+import { getEnergyFlow } from '../../../services/api';
+import { Spin, Typography, Space } from 'antd';
+import { FireOutlined } from '@ant-design/icons';
+
+const { Text } = Typography;
+
+interface Props {
+  realtime?: {
+    pv_power: number;
+    heatpump_power: number;
+    total_load: number;
+    grid_power: number;
+  };
+}
+
+export default function EnergyFlow({ realtime }: Props) {
+  const [flowData, setFlowData] = useState<any>(null);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    getEnergyFlow()
+      .then((data: any) => setFlowData(data))
+      .catch(() => {})
+      .finally(() => setLoading(false));
+  }, []);
+
+  const pv = realtime?.pv_power || 0;
+  const hp = realtime?.heatpump_power || 0;
+  const load = realtime?.total_load || 0;
+  const grid = realtime?.grid_power || 0;
+
+  // Build sankey from realtime data as fallback if API has no flow data
+  const pvToBuilding = Math.min(pv, load);
+  const pvToGrid = Math.max(0, pv - load);
+  const gridToBuilding = Math.max(0, load - pv);
+  const gridToHeatPump = hp;
+
+  const links = flowData?.links || [
+    { source: '光伏发电', target: '建筑用电', value: pvToBuilding || 0.1 },
+    { source: '光伏发电', target: '电网输出', value: pvToGrid || 0.1 },
+    { source: '电网输入', target: '建筑用电', value: gridToBuilding || 0.1 },
+    { source: '电网输入', target: '热泵系统', value: gridToHeatPump || 0.1 },
+  ].filter((l: any) => l.value > 0.05);
+
+  const nodes = flowData?.nodes || [
+    { name: '光伏发电', itemStyle: { color: '#faad14' } },
+    { name: '电网输入', itemStyle: { color: '#52c41a' } },
+    { name: '建筑用电', itemStyle: { color: '#1890ff' } },
+    { name: '电网输出', itemStyle: { color: '#13c2c2' } },
+    { name: '热泵系统', itemStyle: { color: '#f5222d' } },
+  ];
+
+  // Only show nodes that appear in links
+  const usedNames = new Set<string>();
+  links.forEach((l: any) => { usedNames.add(l.source); usedNames.add(l.target); });
+  const filteredNodes = nodes.filter((n: any) => usedNames.has(n.name));
+
+  const option = {
+    tooltip: { trigger: 'item', triggerOn: 'mousemove' },
+    series: [{
+      type: 'sankey',
+      layout: 'none',
+      emphasis: { focus: 'adjacency' },
+      nodeAlign: 'left',
+      orient: 'horizontal',
+      top: 10,
+      bottom: 30,
+      left: 10,
+      right: 10,
+      nodeWidth: 20,
+      nodeGap: 16,
+      data: filteredNodes,
+      links: links,
+      label: { fontSize: 12 },
+      lineStyle: { color: 'gradient', curveness: 0.5 },
+    }],
+  };
+
+  if (loading) return <Spin style={{ display: 'block', margin: '80px auto' }} />;
+
+  return (
+    <div>
+      <ReactECharts option={option} style={{ height: 240 }} />
+      <div style={{ textAlign: 'center', padding: '4px 8px', background: '#fafafa', borderRadius: 8 }}>
+        <Space size={24}>
+          <span><FireOutlined style={{ color: '#f5222d' }} /> 热泵: <Text strong>{hp.toFixed(1)} kW</Text></span>
+          <span>自发自用率: <Text strong style={{ color: '#52c41a' }}>
+            {load > 0 ? ((Math.min(pv, load) / load) * 100).toFixed(1) : 0}%
+          </Text></span>
+        </Space>
+      </div>
+    </div>
+  );
+}