feat(energy): connect to real DB (lingniu_prod)

Replace front-end mock data with live API backed by:
- tab_energy_hydrogen_bill (66.5K rows) joined with
  tab_hydrogen_site (internal stations) and tab_outside_hydrogen_site
  (external stations, joined via inner_site_id)
- tab_energy_electricity_bill (4.4K rows, all 龙王路充电站)

New server routes (src/server/routes/energy/):
- GET /api/energy/hydrogen/overview  → KPI + Top5 站点 + 区域占比
- GET /api/energy/hydrogen/daily?range=&customer=  → 日级 + 站点级下钻
- GET /api/energy/electric/overview  → KPI + 本月柱图 (fallback to last
  available month if current month has no data)
- GET /api/energy/electric/monthly?customer=  → 6 个月分组日级表

Business rules encoded server-side:
- 客户类型: customer_id IS NULL = 羚牛承担, NOT NULL = 外部
- 时区: DATETIME 列字面值是 UTC，分组前 +8h 转成 CST
- 数据清理: hydrogen_time >= 2024-01-01 (排除 1900 年脏数据)
- 站点名 fallback: short_name → name → fixed_station_name → station_name → '未知站点'
- 区域归一化: SUBSTRING_INDEX(city, '-', -1) 取最后一段，去掉 '省'/'市'
  让 '四川省-成都市' 和 '成都市' 合并为 '成都'

Component changes:
- All 4 components (HydrogenOverview, HydrogenDaily, ElectricOverview,
  ElectricDaily) now use useEffect + fetch with loading/error states
- HydrogenDaily filtering moved to server (range + customer params)
  → drops client-side TODAY constant + isInPick switch
- ElectricOverview chart title is dynamic: shows 'YYYY-MM 每日充电'
  when fallback kicks in (current month has no data)
- mock.ts deleted

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

src/modules/energy/ElectricDaily.tsx

@@ -1,18 +1,28 @@
-import { useMemo, useState } from 'react';
+import { useEffect, useState } from 'react';
 import { ChevronRight } from 'lucide-react';
 import { motion, AnimatePresence } from 'motion/react';
 import TrendBadge from './TrendBadge';
-import { ELECTRIC_MONTHLY } from './mock';
-import type { CustomerType } from './types';
+import { fetchElectricMonthly } from './api';
+import type { CustomerType, ElectricMonthGroup } from './types';
 
 export default function ElectricDaily() {
   const [customer, setCustomer] = useState<CustomerType>('external');
-  const [openMonths, setOpenMonths] = useState<Set<string>>(new Set([ELECTRIC_MONTHLY[0]?.month]));
+  const [months, setMonths] = useState<ElectricMonthGroup[] | null>(null);
+  const [openMonths, setOpenMonths] = useState<Set<string>>(new Set());
+  const [error, setError] = useState<string | null>(null);
 
-  const months = useMemo(() => {
-    // mock 暂不区分客户类型，customer 切换不影响数据；保留 UI 切换以与 BI 一致
-    void customer;
-    return ELECTRIC_MONTHLY;
+  useEffect(() => {
+    let cancelled = false;
+    setError(null);
+    fetchElectricMonthly(customer)
+      .then(m => {
+        if (cancelled) return;
+        setMonths(m);
+        // 默认展开最新一个月
+        if (m.length > 0) setOpenMonths(prev => prev.size > 0 ? prev : new Set([m[0].month]));
+      })
+      .catch(e => { if (!cancelled) setError(e instanceof Error ? e.message : String(e)); });
+    return () => { cancelled = true; };
   }, [customer]);
 
   const toggleMonth = (m: string) => setOpenMonths(prev => {
@@ -47,7 +57,13 @@ export default function ElectricDaily() {
           <span className="text-right">充电费用(元)</span>
           <span className="text-right">环比</span>
         </div>
-        {months.map(m => {
+        {error ? (
+          <div className="px-3 py-10 text-center text-red-500 text-[12px] font-bold">加载失败：{error}</div>
+        ) : months === null ? (
+          <div className="px-3 py-10 text-center text-slate-400 text-[12px] font-bold">加载中…</div>
+        ) : months.length === 0 ? (
+          <div className="px-3 py-10 text-center text-slate-400 text-[12px] font-bold">暂无数据</div>
+        ) : months.map(m => {
           const open = openMonths.has(m.month);
           return (
             <div key={m.month} className="border-t border-slate-100 first:border-t-0">