feat: AI预测分析接入真实后端数据 + 修复CloudBilling文件损坏

- AIPredictiveAnalytics: 替换3组硬编码mock为实时数据驱动预测
  - 指标预测: 基于dashboard metrics时序数据(cpu/memory/disk)线性回归计算斜率与R²
  - 容量规划: 基于日均增长率推算阈值触及时间(天),动态生成AI扩容建议
  - 异常预测: 基于告警规则阈值+当前趋势+事件频率计算异常触发概率
  - 概览卡片数据驱动化(置信度基于R²拟合度,高风险/容量预警计数实时计算)
- CloudBilling.tsx: 修复read_file导致的行号前缀损坏(501行全部含N|前缀)

frontend/src/components/ui/confirm-dialog.tsx

@@ -0,0 +1,96 @@
+import { useState, useCallback, createContext, useContext } from 'react';
+import type { ReactNode } from 'react';
+import {
+  Dialog, DialogContent, DialogHeader, DialogTitle,
+  DialogDescription, DialogFooter,
+} from '@/components/ui/dialog';
+import { Button } from '@/components/ui/button';
+
+interface ConfirmOptions {
+  title?: string;
+  description?: string;
+  confirmText?: string;
+  cancelText?: string;
+  variant?: 'default' | 'destructive';
+}
+
+interface ConfirmContextValue {
+  confirm: (options: ConfirmOptions | string) => Promise<boolean>;
+}
+
+const ConfirmContext = createContext<ConfirmContextValue | null>(null);
+
+export function useConfirm() {
+  const ctx = useContext(ConfirmContext);
+  if (!ctx) throw new Error('useConfirm must be used within ConfirmProvider');
+  return ctx.confirm;
+}
+
+export function ConfirmProvider({ children }: { children: ReactNode }) {
+  const [open, setOpen] = useState(false);
+  const [options, setOptions] = useState<Required<ConfirmOptions>>({
+    title: '确认操作',
+    description: '',
+    confirmText: '确认',
+    cancelText: '取消',
+    variant: 'default',
+  });
+  const [resolver, setResolver] = useState<((v: boolean) => void) | null>(null);
+
+  const confirm = useCallback((opts: ConfirmOptions | string) => {
+    const normalized = typeof opts === 'string'
+      ? { title: '确认操作', description: opts }
+      : opts;
+    setOptions({
+      title: normalized.title || '确认操作',
+      description: normalized.description || '',
+      confirmText: normalized.confirmText || '确认',
+      cancelText: normalized.cancelText || '取消',
+      variant: (normalized.variant || 'default') as 'default' | 'destructive',
+    });
+    setOpen(true);
+    return new Promise<boolean>((resolve) => setResolver(() => resolve));
+  }, []);
+
+  const handleConfirm = () => {
+    setOpen(false);
+    resolver?.(true);
+    setResolver(null);
+  };
+
+  const handleCancel = () => {
+    setOpen(false);
+    resolver?.(false);
+    setResolver(null);
+  };
+
+  return (
+    <ConfirmContext.Provider value={{ confirm }}>
+      {children}
+      <Dialog open={open} onOpenChange={(v) => { if (!v) handleCancel(); }}>
+        <DialogContent className="max-w-sm bg-slate-900 border-slate-800" onCloseAutoFocus={(e) => e.preventDefault()}>
+          <DialogHeader>
+            <DialogTitle className="text-slate-100">{options.title}</DialogTitle>
+            {options.description && (
+              <DialogDescription className="text-slate-400">{options.description}</DialogDescription>
+            )}
+          </DialogHeader>
+          <DialogFooter className="gap-2 sm:gap-2">
+            <Button variant="outline" className="border-slate-700 text-slate-300" onClick={handleCancel}>
+              {options.cancelText}
+            </Button>
+            <Button
+              variant={options.variant === 'destructive' ? 'destructive' : 'default'}
+              className={options.variant === 'destructive'
+                ? 'bg-red-600 hover:bg-red-700 text-white'
+                : 'bg-blue-600 hover:bg-blue-700 text-white'}
+              onClick={handleConfirm}
+            >
+              {options.confirmText}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+    </ConfirmContext.Provider>
+  );
+}