修改Web Crypto API 在 HTTP 环境下不可用的问题，自动降级

- HTTPS/localhost ：正常启用加密
- HTTP（非 localhost） ：自动禁用加密，以明文方式通信

video-gen-admin/src/api/client.ts

@@ -3,10 +3,10 @@
  * Handles auth tokens, request/response encryption, snake_case→camelCase conversion.
  */
 
-import { encrypt, decrypt } from './crypto';
+import { encrypt, decrypt, isCryptoAvailable } from './crypto';
 
 const BASE_URL = import.meta.env.VITE_API_BASE || 'http://localhost:8000';
-const USE_ENCRYPTION = !!import.meta.env.VITE_ENCRYPTION_KEY;
+const USE_ENCRYPTION = !!import.meta.env.VITE_ENCRYPTION_KEY && isCryptoAvailable();
 
 interface RequestOptions {
   method?: string;

video-gen-admin/src/api/crypto.ts

@@ -1,6 +1,7 @@
 /**
  * AES-256-GCM encryption/decryption for API request/response.
  * Uses Web Crypto API with a shared symmetric key.
+ * Note: Web Crypto API is only available in secure contexts (HTTPS or localhost).
  */
 
 const ALGO = 'AES-GCM';
@@ -9,10 +10,21 @@ const TAG_LENGTH = 128;
 
 let cryptoKey: CryptoKey | null = null;
 
+export function isCryptoAvailable(): boolean {
+  return typeof window !== 'undefined' && 
+         typeof crypto !== 'undefined' && 
+         typeof crypto.subtle !== 'undefined';
+}
+
 async function getCryptoKey(): Promise<CryptoKey> {
   if (cryptoKey) return cryptoKey;
   const keyB64 = import.meta.env.VITE_ENCRYPTION_KEY || '';
   if (!keyB64) throw new Error('VITE_ENCRYPTION_KEY not configured');
+  
+  if (!isCryptoAvailable()) {
+    throw new Error('Web Crypto API not available (requires HTTPS or localhost)');
+  }
+  
   let keyBytes = Uint8Array.from(atob(keyB64), c => c.charCodeAt(0));
   // AES-256 requires exactly 32 bytes — pad or truncate to match backend
   if (keyBytes.length !== 32) {
@@ -25,6 +37,9 @@ async function getCryptoKey(): Promise<CryptoKey> {
 }
 
 export async function encrypt(plaintext: string): Promise<string> {
+  if (!isCryptoAvailable()) {
+    throw new Error('Encryption not available in non-secure context');
+  }
   const key = await getCryptoKey();
   const iv = crypto.getRandomValues(new Uint8Array(IV_LENGTH));
   const encoded = new TextEncoder().encode(plaintext);
@@ -38,10 +53,13 @@ export async function encrypt(plaintext: string): Promise<string> {
 }
 
 export async function decrypt(cipherB64: string): Promise<string> {
+  if (!isCryptoAvailable()) {
+    throw new Error('Decryption not available in non-secure context');
+  }
   const key = await getCryptoKey();
   const combined = Uint8Array.from(atob(cipherB64), c => c.charCodeAt(0));
   const iv = combined.slice(0, IV_LENGTH);
   const cipherBytes = combined.slice(IV_LENGTH);
   const plainBuf = await crypto.subtle.decrypt({ name: ALGO, iv, tagLength: TAG_LENGTH }, key, cipherBytes);
   return new TextDecoder().decode(plainBuf);
-}
+}