feat(P2): 实现质量保障类5项功能(无障碍/视觉回归/通知渠道/漏洞扫描/灾备)

## 新增功能

### 1. 屏幕阅读器兼容性增强（a11y）
- 无障碍工具库：src/shared/lib/a11y.ts
- aria-live Hook：src/shared/hooks/use-aria-live.ts
- a11y 组件：skip-link/visually-hidden/focus-trap/aria-status
- 增强 UI：table.tsx 系统性 ARIA role，dialog.tsx aria-modal
- 审计文档：docs/accessibility/a11y-audit.md（WCAG 2.1 AA 清单）

### 2. 视觉回归测试
- 测试套件：tests/visual/（homepage + 3 个 dashboard）
- 3 视口（desktop/tablet/mobile）× 2 主题（light/dark）
- 动态元素遮罩，避免误报
- playwright.config.ts 新增 visual-chromium 项目
- 文档：docs/testing/visual-regression.md

### 3. 短信/微信推送渠道集成
- 新模块：src/modules/notifications/
- 4 个渠道：SMS（阿里云/腾讯云）、WeChat（公众号）、Email（SMTP）、In-App
- 分发器按用户偏好并行多渠道发送
- 外部 SDK 动态 import，Mock 模式开发可用
- 文档：docs/notifications/channels.md

### 4. 漏洞扫描 CI 集成
- CI security-scan job：npm audit + Snyk + Trivy FS + OWASP ZAP
- 独立工作流 security.yml：每周一深度扫描 + 容器镜像扫描
- 配置：suppressions.json + .trivyignore
- 本地脚本：security-scan.sh/ps1
- 文档：docs/security/scanning.md（SLA 分级）

### 5. 灾备方案
- 脚本：backup-verify/backup-offsite-sync/dr-drill/failover/health-check
- CI 增强：备份后校验+异地同步，每周灾备演练
- 独立工作流 dr-drill.yml：每周一凌晨 4 点自动演练
- 文档：docs/dr/dr-plan.md（RTO 4h/RPO 24h）+ dr-runbook.md（6 故障场景）

## 验证
- npx tsc --noEmit：0 错误
- npm run lint：0 错误 0 警告

src/shared/components/a11y/aria-status.tsx

@@ -0,0 +1,39 @@
+"use client"
+
+import * as React from "react"
+
+import { cn } from "@/shared/lib/utils"
+
+export interface AriaStatusProps
+  extends React.HTMLAttributes<HTMLDivElement> {
+  children?: React.ReactNode
+  /** 通知礼貌级别，默认 polite */
+  politeness?: "polite" | "assertive"
+  /** 是否原子播报（整体内容），默认 true */
+  atomic?: boolean
+}
+
+/**
+ * ARIA 状态通知区域。
+ * 渲染 aria-live 区域，用于页面级状态通知（如"加载中"、"已保存"）。
+ * 视觉隐藏，仅屏幕阅读器可读。
+ */
+export function AriaStatus({
+  children,
+  politeness = "polite",
+  atomic = true,
+  className,
+  ...props
+}: AriaStatusProps) {
+  return (
+    <div
+      role="status"
+      aria-live={politeness}
+      aria-atomic={atomic}
+      className={cn("sr-only", className)}
+      {...props}
+    >
+      {children}
+    </div>
+  )
+}

src/shared/components/a11y/focus-trap.tsx

@@ -0,0 +1,126 @@
+"use client"
+
+import * as React from "react"
+
+import { cn } from "@/shared/lib/utils"
+
+export interface FocusTrapProps {
+  children: React.ReactNode
+  /** 是否激活焦点陷阱，默认 true */
+  active?: boolean
+  /** 初始焦点元素，未指定时聚焦第一个可聚焦元素 */
+  initialFocusRef?: React.RefObject<HTMLElement | null>
+  /** 关闭时是否恢复焦点到触发元素，默认 true */
+  restoreFocus?: boolean
+  className?: string
+}
+
+const FOCUSABLE_SELECTOR = [
+  "a[href]",
+  "button:not([disabled])",
+  "input:not([disabled])",
+  "textarea:not([disabled])",
+  "select:not([disabled])",
+  "[tabindex]:not([tabindex='-1'])",
+  "[contenteditable='true']",
+  "audio[controls]",
+  "video[controls]",
+].join(",")
+
+/**
+ * 焦点陷阱组件（用于模态框/对话框）。
+ * - 捕获 Tab/Shift+Tab 在容器内循环
+ * - 支持初始焦点元素
+ * - 支持恢复焦点到触发元素
+ */
+export function FocusTrap({
+  children,
+  active = true,
+  initialFocusRef,
+  restoreFocus = true,
+  className,
+}: FocusTrapProps) {
+  const containerRef = React.useRef<HTMLDivElement>(null)
+  const previouslyFocusedRef = React.useRef<HTMLElement | null>(null)
+
+  React.useEffect(() => {
+    if (!active) return
+    previouslyFocusedRef.current = document.activeElement as HTMLElement | null
+
+    const container = containerRef.current
+    if (container) {
+      const focusTarget =
+        initialFocusRef?.current ?? getFirstFocusable(container)
+      if (focusTarget) {
+        focusTarget.focus()
+      }
+    }
+
+    return () => {
+      if (restoreFocus && previouslyFocusedRef.current) {
+        previouslyFocusedRef.current.focus()
+      }
+    }
+  }, [active, initialFocusRef, restoreFocus])
+
+  const handleKeyDown = React.useCallback(
+    (event: React.KeyboardEvent<HTMLDivElement>) => {
+      if (event.key !== "Tab") return
+      const container = containerRef.current
+      if (!container) return
+
+      const focusables = getFocusables(container)
+      if (focusables.length === 0) {
+        event.preventDefault()
+        container.focus()
+        return
+      }
+
+      const first = focusables[0]
+      const last = focusables[focusables.length - 1]
+      const activeEl = document.activeElement
+
+      if (event.shiftKey) {
+        if (activeEl === first || !container.contains(activeEl)) {
+          event.preventDefault()
+          last.focus()
+        }
+      } else {
+        if (activeEl === last || !container.contains(activeEl)) {
+          event.preventDefault()
+          first.focus()
+        }
+      }
+    },
+    []
+  )
+
+  if (!active) {
+    return <>{children}</>
+  }
+
+  return (
+    <div
+      ref={containerRef}
+      onKeyDown={handleKeyDown}
+      tabIndex={-1}
+      className={cn("outline-none", className)}
+    >
+      {children}
+    </div>
+  )
+}
+
+function getFocusables(container: HTMLElement): HTMLElement[] {
+  return Array.from(
+    container.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR)
+  ).filter((el) => {
+    if (el.hasAttribute("disabled")) return false
+    if (el.getAttribute("aria-hidden") === "true") return false
+    return el.offsetParent !== null || el.getClientRects().length > 0
+  })
+}
+
+function getFirstFocusable(container: HTMLElement): HTMLElement | null {
+  return getFocusables(container)[0] ?? null
+}

src/shared/components/a11y/skip-link.tsx

@@ -0,0 +1,39 @@
+"use client"
+
+import * as React from "react"
+
+import { cn } from "@/shared/lib/utils"
+
+export interface SkipLinkProps
+  extends React.AnchorHTMLAttributes<HTMLAnchorElement> {
+  /** 跳转目标锚点，默认 #main-content */
+  href?: string
+  /** 链接文字，默认"跳转到主内容" */
+  children?: React.ReactNode
+}
+
+/**
+ * 跳转链接组件。
+ * 视觉隐藏，获得焦点时高对比度显示，供键盘用户跳过导航直达主内容。
+ */
+export const SkipLink = React.forwardRef<HTMLAnchorElement, SkipLinkProps>(
+  (
+    { href = "#main-content", className, children = "跳转到主内容", ...props },
+    ref
+  ) => {
+    return (
+      <a
+        ref={ref}
+        href={href}
+        className={cn(
+          "sr-only focus:not-sr-only focus:absolute focus:left-4 focus:top-4 focus:z-50 focus:rounded-md focus:border focus:border-border focus:bg-background focus:p-4 focus:text-foreground focus:shadow-lg focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
+          className
+        )}
+        {...props}
+      >
+        {children}
+      </a>
+    )
+  }
+)
+SkipLink.displayName = "SkipLink"

src/shared/components/a11y/visually-hidden.tsx

@@ -0,0 +1,26 @@
+"use client"
+
+import * as React from "react"
+
+import { cn } from "@/shared/lib/utils"
+
+export interface VisuallyHiddenProps
+  extends React.HTMLAttributes<HTMLSpanElement> {
+  children?: React.ReactNode
+}
+
+/**
+ * 视觉隐藏但屏幕阅读器可读的组件。
+ * 用于图标按钮的文字描述、表单标签的辅助说明等。
+ */
+export const VisuallyHidden = React.forwardRef<
+  HTMLSpanElement,
+  VisuallyHiddenProps
+>(({ className, children, ...props }, ref) => {
+  return (
+    <span ref={ref} className={cn("sr-only", className)} {...props}>
+      {children}
+    </span>
+  )
+})
+VisuallyHidden.displayName = "VisuallyHidden"

src/shared/components/ui/dialog.tsx

@@ -37,6 +37,7 @@ const DialogContent = React.forwardRef<
     <DialogOverlay />
     <DialogPrimitive.Content
       ref={ref}
+      aria-modal="true"
       className={cn(
         "fixed left-[50%] top-[50%] z-50 grid w-full max-w-lg translate-x-[-50%] translate-y-[-50%] gap-6 border bg-background p-6 shadow-xl shadow-black/5 duration-200 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 sm:rounded-xl",
         className
@@ -44,9 +45,9 @@ const DialogContent = React.forwardRef<
       {...props}
     >
       {children}
-      <DialogPrimitive.Close className="absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:pointer-events-none data-[state=open]:bg-accent data-[state=open]:text-muted-foreground">
+      <DialogPrimitive.Close aria-label="关闭" className="absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:pointer-events-none data-[state=open]:bg-accent data-[state=open]:text-muted-foreground">
         <X className="h-4 w-4" />
-        <span className="sr-only">Close</span>
+        <span className="sr-only">关闭</span>
       </DialogPrimitive.Close>
     </DialogPrimitive.Content>
   </DialogPortal>

src/shared/components/ui/table.tsx

@@ -5,10 +5,11 @@ import { cn } from "@/shared/lib/utils"
 const Table = React.forwardRef<
   HTMLTableElement,
   React.HTMLAttributes<HTMLTableElement>
->(({ className, ...props }, ref) => (
+>(({ className, role = "table", ...props }, ref) => (
   <div className="relative w-full overflow-auto">
     <table
       ref={ref}
+      role={role}
       className={cn("w-full caption-bottom text-sm", className)}
       {...props}
     />
@@ -19,17 +20,23 @@ Table.displayName = "Table"
 const TableHeader = React.forwardRef<
   HTMLTableSectionElement,
   React.HTMLAttributes<HTMLTableSectionElement>
->(({ className, ...props }, ref) => (
-  <thead ref={ref} className={cn("[&_tr]:border-b", className)} {...props} />
+>(({ className, role = "rowgroup", ...props }, ref) => (
+  <thead
+    ref={ref}
+    role={role}
+    className={cn("[&_tr]:border-b", className)}
+    {...props}
+  />
 ))
 TableHeader.displayName = "TableHeader"
 
 const TableBody = React.forwardRef<
   HTMLTableSectionElement,
   React.HTMLAttributes<HTMLTableSectionElement>
->(({ className, ...props }, ref) => (
+>(({ className, role = "rowgroup", ...props }, ref) => (
   <tbody
     ref={ref}
+    role={role}
     className={cn("[&_tr:last-child]:border-0", className)}
     {...props}
   />
@@ -39,9 +46,10 @@ TableBody.displayName = "TableBody"
 const TableFooter = React.forwardRef<
   HTMLTableSectionElement,
   React.HTMLAttributes<HTMLTableSectionElement>
->(({ className, ...props }, ref) => (
+>(({ className, role = "rowgroup", ...props }, ref) => (
   <tfoot
     ref={ref}
+    role={role}
     className={cn(
       "border-t bg-muted/50 font-medium [&>tr]:last:border-b-0",
       className
@@ -54,9 +62,10 @@ TableFooter.displayName = "TableFooter"
 const TableRow = React.forwardRef<
   HTMLTableRowElement,
   React.HTMLAttributes<HTMLTableRowElement>
->(({ className, ...props }, ref) => (
+>(({ className, role = "row", ...props }, ref) => (
   <tr
     ref={ref}
+    role={role}
     className={cn(
       "border-b transition-colors hover:bg-muted/50 data-[state=selected]:bg-muted",
       className
@@ -69,9 +78,10 @@ TableRow.displayName = "TableRow"
 const TableHead = React.forwardRef<
   HTMLTableCellElement,
   React.ThHTMLAttributes<HTMLTableCellElement>
->(({ className, ...props }, ref) => (
+>(({ className, role = "columnheader", ...props }, ref) => (
   <th
     ref={ref}
+    role={role}
     className={cn(
       "h-10 px-2 text-left align-middle font-medium text-muted-foreground [&:has([role=checkbox])]:pr-0 [&>[role=checkbox]]:translate-y-[2px]",
       className
@@ -84,9 +94,10 @@ TableHead.displayName = "TableHead"
 const TableCell = React.forwardRef<
   HTMLTableCellElement,
   React.TdHTMLAttributes<HTMLTableCellElement>
->(({ className, ...props }, ref) => (
+>(({ className, role = "cell", ...props }, ref) => (
   <td
     ref={ref}
+    role={role}
     className={cn(
       "p-2 align-middle [&:has([role=checkbox])]:pr-0 [&>[role=checkbox]]:translate-y-[2px]",
       className