fix(IM): Redis签名key加入sdkAppId，防止切换AppID后签名不匹配

- key格式: silence:im_user_sig:{sdkAppId}:{identifier}
- 切换IMConfig.sdkAppId后自动缓存miss，重新生成正确签名
- 旧key作为孤儿数据24小时后自然过期

health-im/health-im-biz/src/main/java/com/renkang/im/util/TencentCloudImUtil.java

@@ -48,7 +48,7 @@ public class TencentCloudImUtil {
     @Value("${IMConfig.requestUrl}")
     private String HTTPS_URL_PREFIX;
     private static final String APP_MANAGER = "administrator";
-    private static final String REDIS_IM_USER_SIG = "silence:im_user_sig:";
+    private static final String REDIS_IM_USER_SIG_PREFIX = "silence:im_user_sig:";
 
     @Value("${IMConfig.sdkAppId}")
     private long sdkAppId;
@@ -73,23 +73,29 @@ public class TencentCloudImUtil {
         return System.currentTimeMillis() + "" + StrUtil.subSuf(Math.random() + "", 2);
     }
 
+    private String buildUserSigKey(String identifier) {
+        return REDIS_IM_USER_SIG_PREFIX + sdkAppId + ":" + identifier;
+    }
+
     /**
      * 获取腾讯云用户签名
      */
     public String getTxCloudUserSig() {
-        String userSig = (String) redisServiceUtil.get(REDIS_IM_USER_SIG + APP_MANAGER);
+        String key = buildUserSigKey(APP_MANAGER);
+        String userSig = (String) redisServiceUtil.get(key);
         if (StringUtils.isEmpty(userSig)) {
             userSig = tximUtil.genUserSig(APP_MANAGER);
-            redisServiceUtil.set(REDIS_IM_USER_SIG + APP_MANAGER, userSig, 86400L);
+            redisServiceUtil.set(key, userSig, 86400L);
         }
         return userSig;
     }
 
     public String userSigAndroid(String userId) {
-        String userSig = (String) redisServiceUtil.get(REDIS_IM_USER_SIG + userId);
+        String key = buildUserSigKey(userId);
+        String userSig = (String) redisServiceUtil.get(key);
         if (StringUtils.isEmpty(userSig)) {
             userSig = tximUtil.genUserSig(userId);
-            redisServiceUtil.set(REDIS_IM_USER_SIG + userId, userSig, 86400L);
+            redisServiceUtil.set(key, userSig, 86400L);
         }
         return userSig;
     }