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

scripts/failover.sh

@@ -0,0 +1,419 @@
+#!/bin/bash
+# 故障切换脚本
+# 用法: ./failover.sh [--auto] [--primary URL] [--standby URL]
+# 用于主数据库故障时切换到备库
+
+set -u
+
+show_help() {
+  cat <<EOF
+用法: $0 [选项]
+数据库故障切换脚本,将应用从主库切换到备库
+
+选项:
+  --auto               半自动模式(检测失败后自动切换,需先确认)
+  --primary URL        主库连接 URL(默认从 DATABASE_URL 读取)
+  --standby URL        备库连接 URL(必需,从 DATABASE_URL_STANDBY 读取)
+  --app-url URL        应用健康检查 URL(默认 http://localhost:8015)
+  --no-restart         不重启应用(仅更新配置)
+  --dry-run            演练模式,只输出步骤不实际执行
+  --help, -h           显示帮助信息
+
+环境变量:
+  DATABASE_URL              主库连接 URL
+  DATABASE_URL_STANDBY      备库连接 URL(必需)
+  FAILOVER_APP_URL          应用健康检查 URL(默认 http://localhost:8015)
+  FAILOVER_APP_NAME         应用容器名(默认 nextjs-app)
+  FAILOVER_CONFIG_FILE      配置文件路径(默认 .env.local)
+  FAILOVER_LOG_FILE         切换日志路径(默认 docs/dr/logs/failover.log)
+
+退出码:
+  0  切换成功
+  1  切换失败
+EOF
+}
+
+# 解析参数
+AUTO_MODE=0
+PRIMARY_URL=""
+STANDBY_URL=""
+APP_URL=""
+NO_RESTART=0
+DRY_RUN=0
+
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --help|-h)
+      show_help
+      exit 0
+      ;;
+    --auto)
+      AUTO_MODE=1
+      shift
+      ;;
+    --primary)
+      if [ $# -lt 2 ]; then
+        echo "ERROR: --primary requires an argument" >&2
+        exit 1
+      fi
+      PRIMARY_URL="$2"
+      shift 2
+      ;;
+    --standby)
+      if [ $# -lt 2 ]; then
+        echo "ERROR: --standby requires an argument" >&2
+        exit 1
+      fi
+      STANDBY_URL="$2"
+      shift 2
+      ;;
+    --app-url)
+      if [ $# -lt 2 ]; then
+        echo "ERROR: --app-url requires an argument" >&2
+        exit 1
+      fi
+      APP_URL="$2"
+      shift 2
+      ;;
+    --no-restart)
+      NO_RESTART=1
+      shift
+      ;;
+    --dry-run)
+      DRY_RUN=1
+      shift
+      ;;
+    *)
+      echo "ERROR: Unknown argument: $1" >&2
+      exit 1
+      ;;
+  esac
+done
+
+# 配置
+PRIMARY_URL="${PRIMARY_URL:-${DATABASE_URL:-}}"
+STANDBY_URL="${STANDBY_URL:-${DATABASE_URL_STANDBY:-}}"
+APP_URL="${APP_URL:-${FAILOVER_APP_URL:-http://localhost:8015}}"
+APP_NAME="${FAILOVER_APP_NAME:-nextjs-app}"
+CONFIG_FILE="${FAILOVER_CONFIG_FILE:-.env.local}"
+LOG_DIR="docs/dr/logs"
+LOG_FILE="${FAILOVER_LOG_FILE:-$LOG_DIR/failover.log}"
+
+# 检查必需参数
+if [ -z "$STANDBY_URL" ]; then
+  echo "ERROR: Standby database URL not provided" >&2
+  echo "Set DATABASE_URL_STANDBY or use --standby" >&2
+  exit 1
+fi
+
+if [ -z "$PRIMARY_URL" ]; then
+  echo "ERROR: Primary database URL not provided" >&2
+  echo "Set DATABASE_URL or use --primary" >&2
+  exit 1
+fi
+
+# 创建日志目录
+mkdir -p "$LOG_DIR"
+
+# 日志函数
+log() {
+  local timestamp
+  timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
+  echo "[$timestamp] $1" | tee -a "$LOG_FILE"
+}
+
+log_error() {
+  log "ERROR: $1" >&2
+}
+
+# 解析 DATABASE_URL
+parse_db_url() {
+  local url="$1"
+  local user pass host port dbname
+  user=$(echo "$url" | sed -n 's/.*:\/\/\([^:]*\):.*/\1/p')
+  pass=$(echo "$url" | sed -n 's/.*:\/\/[^:]*:\([^@]*\)@.*/\1/p')
+  host=$(echo "$url" | sed -n 's/.*@\([^:]*\):.*/\1/p')
+  port=$(echo "$url" | sed -n 's/.*:\([0-9]*\)\/.*/\1/p')
+  dbname=$(echo "$url" | sed -n 's/.*\/\([^?]*\).*/\1/p')
+  echo "$user|$pass|$host|$port|$dbname"
+}
+
+# 检查数据库健康
+check_db_health() {
+  local url="$1"
+  local parsed
+  parsed=$(parse_db_url "$url")
+  local user pass host port dbname
+  IFS='|' read -r user pass host port dbname <<EOF
+$parsed
+EOF
+  log "Checking database health: ${host}:${port}/${dbname}"
+  if [ "$DRY_RUN" -eq 1 ]; then
+    log "  [DRY-RUN] Would check: mysql -h $host -P $port -u $user -e 'SELECT 1'"
+    return 0
+  fi
+  if mysql -h "$host" -P "$port" -u "$user" -p"$pass" -e "SELECT 1;" 2>/dev/null; then
+    log "  Database is healthy"
+    return 0
+  else
+    log "  Database is NOT reachable"
+    return 1
+  fi
+}
+
+# 检查应用健康
+check_app_health() {
+  local url="$1"
+  log "Checking application health: $url"
+  if [ "$DRY_RUN" -eq 1 ]; then
+    log "  [DRY-RUN] Would check: curl -f $url"
+    return 0
+  fi
+  if command -v curl >/dev/null 2>&1; then
+    if curl -sf -o /dev/null -m 10 "$url" 2>/dev/null; then
+      log "  Application is healthy"
+      return 0
+    else
+      log "  Application is NOT healthy"
+      return 1
+    fi
+  else
+    log "  WARN: curl not available, skipping app health check"
+    return 0
+  fi
+}
+
+# 提升备库为主库(如果是主从架构)
+promote_standby() {
+  log "Promoting standby to primary..."
+  local parsed
+  parsed=$(parse_db_url "$STANDBY_URL")
+  local user pass host port dbname
+  IFS='|' read -r user pass host port dbname <<EOF
+$parsed
+EOF
+
+  if [ "$DRY_RUN" -eq 1 ]; then
+    log "  [DRY-RUN] Would promote standby: STOP SLAVE; RESET SLAVE ALL; SET GLOBAL read_only=OFF;"
+    return 0
+  fi
+
+  # 检查是否为从库
+  SLAVE_STATUS=$(mysql -h "$host" -P "$port" -u "$user" -p"$pass" \
+      -e "SHOW SLAVE STATUS\G" 2>/dev/null)
+
+  if [ -n "$SLAVE_STATUS" ]; then
+    log "  Standby is a slave, promoting..."
+    # 停止复制
+    if mysql -h "$host" -P "$port" -u "$user" -p"$pass" \
+        -e "STOP SLAVE; RESET SLAVE ALL;" 2>/dev/null; then
+      log "  Replication stopped and reset"
+    else
+      log_error "Failed to stop replication"
+      return 1
+    fi
+    # 关闭只读模式
+    if mysql -h "$host" -P "$port" -u "$user" -p"$pass" \
+        -e "SET GLOBAL read_only=OFF; SET GLOBAL super_read_only=OFF;" 2>/dev/null; then
+      log "  Read-only mode disabled"
+    else
+      log_error "Failed to disable read-only mode"
+      return 1
+    fi
+  else
+    log "  Standby is not a slave (standalone), skipping promotion"
+  fi
+
+  log "  Standby promoted successfully"
+  return 0
+}
+
+# 更新应用配置
+update_config() {
+  log "Updating application configuration..."
+  if [ "$DRY_RUN" -eq 1 ]; then
+    log "  [DRY-RUN] Would update $CONFIG_FILE: DATABASE_URL=$STANDBY_URL"
+    return 0
+  fi
+
+  if [ -f "$CONFIG_FILE" ]; then
+    # 备份原配置
+    cp "$CONFIG_FILE" "${CONFIG_FILE}.bak.$(date +%s)"
+    log "  Backed up original config to ${CONFIG_FILE}.bak.*"
+
+    # 更新 DATABASE_URL
+    if grep -q "^DATABASE_URL=" "$CONFIG_FILE"; then
+      sed -i.bak "s|^DATABASE_URL=.*|DATABASE_URL=$STANDBY_URL|" "$CONFIG_FILE"
+      rm -f "${CONFIG_FILE}.bak" 2>/dev/null || true
+      log "  Updated DATABASE_URL in $CONFIG_FILE"
+    else
+      echo "DATABASE_URL=$STANDBY_URL" >> "$CONFIG_FILE"
+      log "  Added DATABASE_URL to $CONFIG_FILE"
+    fi
+  else
+    log "  WARN: Config file $CONFIG_FILE not found, creating new one"
+    echo "DATABASE_URL=$STANDBY_URL" > "$CONFIG_FILE"
+  fi
+
+  # 同时更新环境变量(供当前会话使用)
+  export DATABASE_URL="$STANDBY_URL"
+  log "  Configuration updated"
+  return 0
+}
+
+# 重启应用
+restart_app() {
+  if [ "$NO_RESTART" -eq 1 ]; then
+    log "Skipping application restart (--no-restart)"
+    return 0
+  fi
+
+  log "Restarting application..."
+  if [ "$DRY_RUN" -eq 1 ]; then
+    log "  [DRY-RUN] Would restart: docker restart $APP_NAME"
+    return 0
+  fi
+
+  if command -v docker >/dev/null 2>&1; then
+    log "  Restarting Docker container: $APP_NAME"
+    if docker restart "$APP_NAME" 2>/dev/null; then
+      log "  Container restarted"
+      # 等待应用启动
+      log "  Waiting for application to start..."
+      sleep 5
+      return 0
+    else
+      log_error "Failed to restart container $APP_NAME"
+      return 1
+    fi
+  else
+    log "  WARN: Docker not available, please restart application manually"
+    log "  Updated DATABASE_URL: $STANDBY_URL"
+  fi
+  return 0
+}
+
+# 主流程
+log "========================================"
+log "Database Failover Started"
+log "========================================"
+log "Mode: $([ "$AUTO_MODE" -eq 1 ] && echo "semi-auto" || echo "manual")"
+log "Dry-run: $([ "$DRY_RUN" -eq 1 ] && echo "yes" || echo "no")"
+log "Primary: $PRIMARY_URL"
+log "Standby: $STANDBY_URL"
+log ""
+
+# 步骤 1: 检测主库健康状态
+log "[1/5] Checking primary database health..."
+PRIMARY_HEALTHY=0
+if check_db_health "$PRIMARY_URL"; then
+  PRIMARY_HEALTHY=1
+  log "  Primary is healthy"
+  if [ "$AUTO_MODE" -eq 0 ]; then
+    log "  Primary is healthy. Failover not needed."
+    log "  Use --auto to force failover even if primary is healthy"
+    log "========================================"
+    log "Failover Cancelled (Primary Healthy)"
+    log "========================================"
+    exit 0
+  fi
+else
+  log "  Primary is NOT healthy, proceeding with failover"
+fi
+
+# 半自动模式确认
+if [ "$AUTO_MODE" -eq 1 ] && [ "$DRY_RUN" -eq 0 ]; then
+  echo ""
+  echo "WARNING: About to failover from primary to standby."
+  echo "  Primary: $PRIMARY_URL"
+  echo "  Standby: $STANDBY_URL"
+  echo ""
+  read -p "Type 'FAILover' to confirm: " CONFIRM
+  if [ "$CONFIRM" != "FAILover" ]; then
+    log "Failover cancelled by user"
+    exit 1
+  fi
+fi
+
+# 步骤 2: 检查备库健康
+log ""
+log "[2/5] Checking standby database health..."
+if ! check_db_health "$STANDBY_URL"; then
+  log_error "Standby is also not healthy, cannot failover"
+  log "========================================"
+  log "Failover FAILED (Standby Unhealthy)"
+  log "========================================"
+  exit 1
+fi
+
+# 步骤 3: 提升备库为主库
+log ""
+log "[3/5] Promoting standby to primary..."
+if ! promote_standby; then
+  log_error "Failed to promote standby"
+  exit 1
+fi
+
+# 步骤 4: 更新应用配置并重启
+log ""
+log "[4/5] Updating application configuration and restarting..."
+update_config
+if ! restart_app; then
+  log_error "Failed to restart application"
+  log "  Manual intervention required"
+  exit 1
+fi
+
+# 步骤 5: 验证切换成功
+log ""
+log "[5/5] Verifying failover..."
+sleep 3
+
+# 检查应用健康
+APP_HEALTHY=0
+for i in 1 2 3 4 5; do
+  if check_app_health "$APP_URL"; then
+    APP_HEALTHY=1
+    break
+  fi
+  log "  Retry $i/5 in 5 seconds..."
+  sleep 5
+done
+
+if [ "$APP_HEALTHY" -eq 0 ]; then
+  log_error "Application is not healthy after failover"
+  log "  Check application logs and configuration"
+  log "========================================"
+  log "Failover FAILED (App Unhealthy)"
+  log "========================================"
+  exit 1
+fi
+
+# 检查数据库连接(通过应用)
+log "  Verifying database connection via application..."
+if [ "$DRY_RUN" -eq 0 ]; then
+  if curl -sf -m 10 "$APP_URL" >/dev/null 2>&1; then
+    log "  Application responding successfully"
+  else
+    log_error "Application not responding"
+    exit 1
+  fi
+fi
+
+log ""
+log "========================================"
+log "Failover Completed Successfully"
+log "========================================"
+log "Primary (old):   $PRIMARY_URL"
+log "Standby (new):   $STANDBY_URL"
+log "Application:     $APP_URL"
+log "Log file:        $LOG_FILE"
+log ""
+log "Post-failover checklist:"
+log "  1. Verify application functionality"
+log "  2. Update monitoring alerts"
+log "  3. Notify stakeholders"
+log "  4. Plan primary database recovery"
+log "  5. Schedule post-mortem review"
+log ""
+exit 0