fix(ssf): 修复安全事件连接基础阻断

为已记录旧迁移版本的环境补充幂等表修复迁移，并让 Transmitter 网络连接在 IPv6 地址不可达时继续尝试 IPv4。失败连接现在通过 If-Match 安全重试，页面同步提供重试入口并清理过期错误提示。\n\n验证：Go securityevents/migrate 测试、Web Vitest 与 TypeScript 类型检查通过。

apps/web/src/api.ts

@@ -1007,10 +1007,12 @@ export async function getSecurityEventConnection(token: string): Promise<Securit
   return request<SecurityEventConnectionResponse>(securityEventConnectionPath, { token });
 }
 
-export async function connectSecurityEventTransmitter(token: string, transmitterIssuer: string): Promise<SecurityEventConnectionResponse> {
+export async function connectSecurityEventTransmitter(token: string, transmitterIssuer: string, version?: number): Promise<SecurityEventConnectionResponse> {
+  const headers: Record<string, string> = { 'Idempotency-Key': `ssf-connect-${crypto.randomUUID()}` };
+  if (version !== undefined) headers['If-Match'] = `W/"${version}"`;
   return request<SecurityEventConnectionResponse>(securityEventConnectionPath, {
     body: { transmitter_issuer: transmitterIssuer }, method: 'PUT', token,
-    headers: { 'Idempotency-Key': `ssf-connect-${crypto.randomUUID()}` },
+    headers,
   });
 }