Improve failover startup handling and status UI

src/server/services/singboxSelectorService.ts

@@ -6,6 +6,25 @@ import {
 } from '../singbox.js';
 
 type Role = 'primary' | 'reserve';
+const SELECTOR_READY_ATTEMPTS = 20;
+const SELECTOR_READY_DELAY_MS = 100;
+
+const transientStartupError = (error: unknown) => (
+  error && typeof error === 'object' && 'code' in error
+    ? ['ECONNREFUSED', 'ECONNRESET'].includes(String(error.code))
+    : false
+);
+
+async function whenReady<T>(operation: () => Promise<T>): Promise<T> {
+  for (let attempt = 1; ; attempt += 1) {
+    try {
+      return await operation();
+    } catch (error) {
+      if (!transientStartupError(error) || attempt === SELECTOR_READY_ATTEMPTS) throw error;
+      await new Promise((resolve) => setTimeout(resolve, SELECTOR_READY_DELAY_MS));
+    }
+  }
+}
 
 function request(port: number, method: string, body?: unknown): Promise<unknown> {
   return new Promise((resolve, reject) => {
@@ -51,13 +70,13 @@ export function createSingboxSelectorService({
   send?: (method: string, body?: unknown) => Promise<unknown>;
 }) {
   async function read() {
-    const value = await send('GET') as Record<string, unknown>;
+    const value = await whenReady(() => send('GET')) as Record<string, unknown>;
     const role = roleFor(value.now);
     if (!role) throw new Error('Sing-box selector вернул неизвестный outbound');
     return { role };
   }
   async function select(role: Role) {
-    await send('PUT', { name: tagFor(role) });
+    await whenReady(() => send('PUT', { name: tagFor(role) }));
     const selected = await read();
     if (selected.role !== role) throw new Error('Sing-box selector не подтвердил переключение');
     return selected;