fix: 修复开始表单旧工作流兼容回退

- 避免旧开始节点缺失 user_input 时运行态强行注入系统问题字段

- 补充运行参数解析兼容测试并收口 M12 尾项

easyflow-modules/easyflow-module-ai/src/main/java/tech/easyflow/ai/easyagentsflow/service/WorkflowRunningParameterResolver.java

@@ -128,6 +128,10 @@ public class WorkflowRunningParameterResolver {
         JSONArray rawSchema = startNodeData == null ? null : startNodeData.getJSONArray("startFormSchema");
         List<Map<String, Object>> schema = new ArrayList<>();
         Set<String> seenKeys = new LinkedHashSet<>();
+        boolean hasExplicitSchema = rawSchema != null;
+        boolean hasSystemParameter = parameters.stream().anyMatch(parameter ->
+                SYSTEM_START_PARAM_NAME.equals(trimToNull(parameter == null ? null : parameter.getName()))
+        );
         if (rawSchema != null && !rawSchema.isEmpty()) {
             for (int i = 0; i < rawSchema.size(); i++) {
                 JSONObject field = rawSchema.getJSONObject(i);
@@ -163,7 +167,7 @@ public class WorkflowRunningParameterResolver {
                 }
             }
         }
-        if (!seenKeys.contains(SYSTEM_START_PARAM_NAME)) {
+        if (!seenKeys.contains(SYSTEM_START_PARAM_NAME) && (hasExplicitSchema || hasSystemParameter)) {
             schema.add(0, normalizeStartFormField(new JSONObject(), null));
         }
         return schema;