feat(web,plugin): P1 跨插件引用 — 前端 Phase 4

- plugins.ts: PluginFieldSchema 新增 ref_plugin/ref_fallback_label, PluginEntitySchema 新增 is_public
- pluginData.ts: 新增 resolveRefLabels/getPluginEntityRegistry API
- EntitySelect: 支持 refPlugin 跨插件查询，目标不可用时降级为禁用 Input
- PluginCRUDPage: 表格列解析引用标签（蓝色 Tag），entity_select 表单传 refPlugin/fallbackLabel

apps/web/src/api/pluginData.ts

@@ -171,3 +171,40 @@ export async function getPluginTimeseries(
   );
   return data.data;
 }
+
+// ─── 跨插件引用 API ──────────────────────────────────────────────────
+
+export interface ResolveLabelsResult {
+  labels: Record<string, Record<string, string | null>>;
+  meta: Record<string, {
+    target_plugin: string;
+    target_entity: string;
+    label_field: string;
+    plugin_installed: boolean;
+  }>;
+}
+
+export async function resolveRefLabels(
+  pluginId: string,
+  entity: string,
+  fields: Record<string, string[]>,
+): Promise<ResolveLabelsResult> {
+  const { data } = await client.post<{ success: boolean; data: ResolveLabelsResult }>(
+    `/plugins/${pluginId}/${entity}/resolve-labels`,
+    { fields },
+  );
+  return data.data;
+}
+
+export interface PublicEntity {
+  manifest_id: string;
+  entity_name: string;
+  display_name: string;
+}
+
+export async function getPluginEntityRegistry(): Promise<PublicEntity[]> {
+  const { data } = await client.get<{ success: boolean; data: PublicEntity[] }>(
+    '/plugin-registry/entities',
+  );
+  return data.data;
+}