feat(chat): 实现聊天界面功能并完善文档说明

- 新增AttachmentRepository处理图片、视频、音频、文件发送功能
- 实现AuthRepository管理用户认证和会话状态
- 添加EnvironmentRepository支持环境配置切换
- 完成ChatScreen界面实现，包含消息收发、媒体文件处理
- 更新设计文档补充Android聊天页历史加载和测试验证说明
- 添加联系人黑名单错误信息返回和IM验证流程调整说明

demo-service/src/main/java/com/xuqm/demo/service/DemoAuthService.java

@@ -19,6 +19,7 @@ import org.springframework.transaction.annotation.Transactional;
 import org.springframework.web.client.RestClientException;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.util.UriComponentsBuilder;
+import java.net.URI;
 
 import java.time.Instant;
 import java.util.Map;
@@ -139,12 +140,14 @@ public class DemoAuthService {
         String payload = AppRequestSignatureUtil.payload(appId, userId, effectiveNickname, null, timestamp, nonce);
         String signature = AppRequestSignatureUtil.sign(appSecret, payload);
 
-        String url = UriComponentsBuilder.fromHttpUrl(imServiceUrl)
+        URI uri = UriComponentsBuilder.fromHttpUrl(imServiceUrl)
                 .path("/api/im/auth/login")
                 .queryParam("appId", appId)
                 .queryParam("userId", userId)
                 .queryParam("nickname", effectiveNickname)
-                .toUriString();
+                .encode()
+                .build()
+                .toUri();
 
         try {
             HttpHeaders headers = new HttpHeaders();
@@ -152,7 +155,7 @@ public class DemoAuthService {
             headers.set("X-App-Nonce", nonce);
             headers.set("X-App-Signature", signature);
             ResponseEntity<JsonNode> response = restTemplate.exchange(
-                    url,
+                    uri,
                     HttpMethod.POST,
                     new HttpEntity<>(headers),
                     JsonNode.class