首页工作流节点引用多选与保存回显完善：isMultiParameter 全链路透传 + valueSource 数组化/label + 旧 DSL 兼容

- isMultiParameter 节点级开关从节点库透传至引用下拉，支持多选勾选/去重/逐条删除/清空
- valueSource 契约统一为数组并补 label（节点名.字段中文名），覆盖用户引用、表单展示标记与旧 DSL 单对象
- ModelField 递归透传 multi，object/array 嵌套子字段同样支持多选
- 保存/回显兼容旧 DSL 单对象 valueSource，重开自动升级为数组
- modelRequestParamsPath 每项新增 label 字段，后端按 path 重组请求参数

Co-Authored-By: Claude <noreply@anthropic.com>

src/views/settings/workflow/component/ModelParamsForm.vue

@@ -14,6 +14,7 @@
 					:field-def="def"
 					:path="key"
 					:upstream-nodes="upstreamNodes"
+					:multi="multi"
 				/>
 			</div>
 		</div>
@@ -33,7 +34,7 @@ interface UpstreamNodeInfo {
 	outputFields: { field: string; label: string }[];
 }
 
-const props = defineProps<{ modelRequestParams: Record<string, any> | null; upstreamNodes?: UpstreamNodeInfo[] }>();
+const props = defineProps<{ modelRequestParams: Record<string, any> | null; upstreamNodes?: UpstreamNodeInfo[]; multi?: boolean }>();
 const emit = defineEmits<{ 'update:modelRequestParams': [Record<string, any> | null] }>();
 
 const localParams = ref<Record<string, any>>({});