fix: 防止开始节点重名参数被删除

- 校验开始节点参数名并保留冲突输入

- 在字段归一化前拦截重名并补充回归测试

easyflow-ui-admin/packages/tinyflow-ui/src/components/core/DefinedParameterItem.svelte

@@ -7,6 +7,7 @@
   import {useTinyflowStore} from '#store/stores.svelte';
   import {getCurrentNodeId} from '#components/utils/NodeUtils';
   import {
+    isStartFormFieldKeyAvailable,
     renameStartFieldReferencesInNodes,
     removeStartFormField,
     START_NODE_TYPE,
@@ -47,12 +48,15 @@
         }
         return param.formType ? [param.formType] : [];
     });
+    let parameterNameDraft = $state<string | null>(null);
     let displayParamName = $derived.by(() => {
         if (isSystemStartParam) {
             return '用户问题';
         }
-        return param.name;
+        return parameterNameDraft ?? param.name;
     });
+    let parameterNameError = $state('');
+    let parameterNameErrorId = $derived(`parameter-name-error-${param.id || index}`);
 
     const { updateNodeData } = useSvelteFlow();
 
@@ -146,7 +150,27 @@
     };
 
     const updateName = (event: Event) => {
-        const newValue = (event.target as any).value;
+        const input = event.target as HTMLInputElement;
+        const newValue = input.value;
+        if (isStartNodeInputParam) {
+            const normalizedValue = trimString(newValue);
+            if (!normalizedValue) {
+                parameterNameError = '参数名不能为空';
+                parameterNameDraft = newValue;
+                return;
+            }
+            if (!isStartFormFieldKeyAvailable(
+                node?.current?.data as Record<string, any>,
+                param.name || '',
+                normalizedValue
+            )) {
+                parameterNameError = '参数名已存在';
+                parameterNameDraft = newValue;
+                return;
+            }
+        }
+        parameterNameDraft = null;
+        parameterNameError = '';
         updateParameter('name', newValue);
     };
 
@@ -191,10 +215,17 @@
 </script>
 
 
-<div class="input-item">
+<div class="input-item input-item-name">
     <Input style="width: 100%;" value={displayParamName} placeholder="请输入参数名称"
            disabled={param.nameDisabled === true}
+           aria-invalid={parameterNameError ? 'true' : undefined}
+           aria-describedby={parameterNameError ? parameterNameErrorId : undefined}
            oninput={updateName} />
+    {#if parameterNameError}
+        <div id={parameterNameErrorId} class="input-error" role="alert">
+            {parameterNameError}
+        </div>
+    {/if}
 </div>
 <div class="input-item">
     <Checkbox checked={param.required} disabled={param.requiredDisabled === true} onchange={updateRequired} />
@@ -276,6 +307,22 @@
     align-items: center;
   }
 
+  .input-item-name {
+    flex-direction: column;
+    align-items: stretch;
+    gap: 3px;
+  }
+
+  .input-error {
+    font-size: 12px;
+    line-height: 1.4;
+    color: var(--tf-danger-soft-text);
+  }
+
+  :global(.tf-input[aria-invalid='true']) {
+    border-color: var(--tf-danger-soft-border);
+  }
+
   .input-more-setting {
     display: flex;
     flex-direction: column;

easyflow-ui-admin/packages/tinyflow-ui/src/utils/workflowNodeFields.test.ts

@@ -13,6 +13,7 @@ import {
   createInitialWorkflowData,
   ensureStartNodeParameters,
   FIELD_BINDING_META_KEY,
+  isStartFormFieldKeyAvailable,
   normalizeStartNodeData,
   normalizeWorkflowStartNodes,
   renameStartFieldReferencesInNodes,
@@ -148,6 +149,47 @@ describe('workflow node fields', () => {
     expect(nextParameter?.id).toBe(previousParameter?.id);
   });
 
+  it('keeps start fields unchanged when renaming to an existing key', () => {
+    const initial = createInitialWorkflowData();
+    const withTopic = appendStartFormField(
+      initial.nodes[0]?.data as Record<string, any>,
+      {
+        key: 'topic',
+        label: '主题',
+        type: 'text',
+      },
+    );
+    const withDetails = appendStartFormField(withTopic, {
+      key: 'details',
+      label: '详情',
+      type: 'textarea',
+    });
+    const previousFields = withDetails.startFormSchema;
+    const previousParameters = withDetails.parameters;
+
+    expect(
+      isStartFormFieldKeyAvailable(withDetails, 'details', 'summary'),
+    ).toBe(true);
+    expect(
+      isStartFormFieldKeyAvailable(withDetails, 'details', 'topic'),
+    ).toBe(false);
+    expect(
+      isStartFormFieldKeyAvailable(withDetails, 'details', 'user_input'),
+    ).toBe(false);
+
+    const duplicatedCustomKey = updateStartFormField(withDetails, 'details', {
+      key: 'topic',
+    });
+    const duplicatedSystemKey = updateStartFormField(withDetails, 'details', {
+      key: 'user_input',
+    });
+
+    expect(duplicatedCustomKey.startFormSchema).toEqual(previousFields);
+    expect(duplicatedCustomKey.parameters).toEqual(previousParameters);
+    expect(duplicatedSystemKey.startFormSchema).toEqual(previousFields);
+    expect(duplicatedSystemKey.parameters).toEqual(previousParameters);
+  });
+
   it('renames downstream token and managed references when start field key changes', () => {
     const initialStartData = appendStartFormField(
       createInitialWorkflowData().nodes[0]?.data as Record<string, any>,

easyflow-ui-admin/packages/tinyflow-ui/src/utils/workflowNodeFields.ts

@@ -720,6 +720,36 @@ export function normalizeStartFormSchema(
   return result;
 }
 
+export function isStartFormFieldKeyAvailable(
+  data: Record<string, any> | null | undefined,
+  currentKey: string,
+  candidateKey: string,
+) {
+  const normalizedCurrentKey = trimString(currentKey);
+  const normalizedCandidateKey = trimString(candidateKey);
+  if (!normalizedCurrentKey || !normalizedCandidateKey) {
+    return false;
+  }
+
+  const currentData = (data || {}) as Record<string, any>;
+  const currentParameters = Array.isArray(currentData.parameters)
+    ? (currentData.parameters as Parameter[])
+    : [];
+  const schema = normalizeStartFormSchema(
+    currentData.startFormSchema,
+    currentParameters,
+  );
+  if (!schema.some((field) => field.key === normalizedCurrentKey)) {
+    return false;
+  }
+
+  return !schema.some(
+    (field) =>
+      field.key === normalizedCandidateKey &&
+      field.key !== normalizedCurrentKey,
+  );
+}
+
 export function createCustomStartFormField(
   field?: Partial<StartFormFieldSchema> | null,
   existingKeys: string[] = [],
@@ -773,6 +803,12 @@ export function updateStartFormField(
     ? (currentData.parameters as Parameter[])
     : [];
   const schema = normalizeStartFormSchema(currentData.startFormSchema, currentParameters);
+  if (
+    patch.key !== undefined &&
+    !isStartFormFieldKeyAvailable(currentData, currentKey, patch.key)
+  ) {
+    return normalizeStartNodeData(currentData);
+  }
   const nextSchema = schema.map((field) => {
     if (field.key !== currentKey) {
       return field;