feat(admin-ui): members panel, invite links, audit tab and role-aware console

- New MembersPanel: role switching, add/remove members, invite-link
  generation with copy/revoke, pending invite list
- New Audit tab (AuditLog.vue) with group filter
- Role-aware UI: viewer hides route/group edit actions (RouteCard readonly),
  owner-only controls, role badge + member count on group cards
- GroupEditor: members managed via panel, owners field super-admin only
- en/zh i18n and CSS for the new panels

admin/composables/useGroups.ts

@@ -1,12 +1,28 @@
-import type { Group } from "~/types";
+import type { Group, GroupRole } from "~/types";
 
 export function useGroupsApi() {
   const groups = ref<Group[]>([]);
   const isSuper = ref(false);
+  /** groupId → role of the signed-in user (absent for super admins). */
+  const roles = ref<Record<string, GroupRole>>({});
   const loading = ref(false);
   const needLogin = ref(false);
   const error = ref("");
 
+  function roleOf(groupId: string): GroupRole | undefined {
+    return isSuper.value ? "owner" : roles.value[groupId];
+  }
+
+  function canEditGroup(groupId: string): boolean {
+    const r = roleOf(groupId);
+    return isSuper.value || r === "owner";
+  }
+
+  function canEditRoutes(groupId: string): boolean {
+    const r = roleOf(groupId);
+    return isSuper.value || r === "owner" || r === "admin";
+  }
+
   async function load(): Promise<void> {
     loading.value = true;
     error.value = "";
@@ -21,9 +37,14 @@ export function useGroupsApi() {
         return;
       }
       if (!res.ok) throw new Error(`HTTP ${res.status}`);
-      const data = (await res.json()) as { groups?: Group[]; isSuper?: boolean };
+      const data = (await res.json()) as {
+        groups?: Group[];
+        isSuper?: boolean;
+        roles?: Record<string, GroupRole>;
+      };
       groups.value = data.groups ?? [];
       isSuper.value = data.isSuper ?? false;
+      roles.value = data.roles ?? {};
     } catch (err) {
       error.value = err instanceof Error ? err.message : String(err);
     } finally {
@@ -49,5 +70,5 @@ export function useGroupsApi() {
     groups.value = next;
   }
 
-  return { groups, isSuper, loading, needLogin, error, load, save };
+  return { groups, isSuper, roles, roleOf, canEditGroup, canEditRoutes, loading, needLogin, error, load, save };
 }