fix: 保留流式输出连续重复字符

- 按 AgentScope 增量协议原样保留普通文本分片

- 仅在终态完整快照中去除已发送前缀

- 补充连续端口字符回归测试

easy-agents-agent-runtime/src/test/java/com/easyagents/agent/runtime/agentscope/AgentScopeStatefulRuntimeTest.java

@@ -690,6 +690,49 @@ public class AgentScopeStatefulRuntimeTest {
         Assert.assertTrue(sessionStore.exists("session-1"));
     }
 
+    /**
+     * 验证增量模式会保留 URL 中连续出现的相同字符。
+     */
+    @Test
+    public void shouldPreserveRepeatedIdenticalTextDeltas() {
+        String expectedUrl = "http://127.0.0.1:39000/easyflow/file.docx";
+        AgentScopeReActRuntime runtime = runtimeWithStreamingModel(List.of(
+                ChatResponse.builder()
+                        .id("url-response")
+                        .content(List.of(TextBlock.builder().text("http://127.0.0.1:39").build()))
+                        .build(),
+                ChatResponse.builder()
+                        .id("url-response")
+                        .content(List.of(TextBlock.builder().text("0").build()))
+                        .build(),
+                ChatResponse.builder()
+                        .id("url-response")
+                        .content(List.of(TextBlock.builder().text("0").build()))
+                        .build(),
+                ChatResponse.builder()
+                        .id("url-response")
+                        .content(List.of(TextBlock.builder().text("0/easyflow/file.docx").build()))
+                        .finishReason("stop")
+                        .build()));
+        runtime.init(initRequest());
+
+        List<AgentRuntimeEvent> events = runtime.stream(
+                        AgentMessage.text(AgentMessageRole.USER, "create file"))
+                .collectList()
+                .block();
+        String streamedText = events.stream()
+                .filter(event -> event.getEventType() == AgentRuntimeEventType.MESSAGE_DELTA)
+                .map(event -> String.valueOf(event.getPayload().getOrDefault("text", "")))
+                .reduce("", String::concat);
+
+        Assert.assertEquals(expectedUrl, streamedText);
+        AgentRuntimeEvent completed = events.stream()
+                .filter(event -> event.getEventType() == AgentRuntimeEventType.COMPLETED)
+                .findFirst()
+                .orElseThrow();
+        Assert.assertEquals(expectedUrl, completed.getPayload().get("text"));
+    }
+
     @Test
     public void shouldAllowNextStreamAfterPreviousStreamCompleted() {
         AgentScopeReActRuntime runtime = fakeRuntime();
@@ -1370,6 +1413,27 @@ public class AgentScopeStatefulRuntimeTest {
                 new AgentScopeMessageAdapter());
     }
 
+    /**
+     * 创建单次模型调用返回多个增量响应的运行时。
+     *
+     * @param responses 同一次模型调用中的响应增量
+     * @return 测试运行时
+     */
+    private AgentScopeReActRuntime runtimeWithStreamingModel(List<ChatResponse> responses) {
+        AgentScopeModelFactory modelFactory = new AgentScopeModelFactory() {
+            @Override
+            public Model create(AgentModelSpec modelSpec,
+                                com.easyagents.agent.runtime.model.AgentGenerationOptions generationOptions) {
+                return new StreamingScriptedModel(
+                        modelSpec == null ? "fake-model" : modelSpec.getModelName(),
+                        responses);
+            }
+        };
+        return new AgentScopeReActRuntime(modelFactory, new AgentScopeToolAdapter(),
+                new AgentScopeKnowledgeAdapter(), new AgentScopeMemoryAdapter(), new AgentScopeSkillAdapter(),
+                new AgentScopeMessageAdapter());
+    }
+
     /**
      * 根据审批事件创建恢复请求。
      *
@@ -1419,6 +1483,51 @@ public class AgentScopeStatefulRuntimeTest {
         }
     }
 
+    /**
+     * 单次调用按顺序返回全部响应增量的测试模型。
+     */
+    private static class StreamingScriptedModel implements Model {
+
+        private final String modelName;
+        private final List<ChatResponse> responses;
+
+        /**
+         * 创建流式测试模型。
+         *
+         * @param modelName 模型名称
+         * @param responses 响应增量
+         */
+        private StreamingScriptedModel(String modelName, List<ChatResponse> responses) {
+            this.modelName = modelName;
+            this.responses = responses;
+        }
+
+        /**
+         * 返回预设的响应增量。
+         *
+         * @param messages 输入消息
+         * @param toolSchemas 工具定义
+         * @param options 生成配置
+         * @return 响应流
+         */
+        @Override
+        public Flux<ChatResponse> stream(List<Msg> messages,
+                                         List<ToolSchema> toolSchemas,
+                                         GenerateOptions options) {
+            return Flux.fromIterable(responses);
+        }
+
+        /**
+         * 获取模型名称。
+         *
+         * @return 模型名称
+         */
+        @Override
+        public String getModelName() {
+            return modelName;
+        }
+    }
+
     private AgentInitRequest initRequest() {
         AgentModelSpec modelSpec = new AgentModelSpec();
         modelSpec.setModelName("fake-model");