fix(templates): wire template detail page to real content service

/templates/[id] only searched the hardcoded demo catalog, so real published
containers (e.g. insta-promo) 404'd even though the browser listed and linked them.
Now resolveTemplate() fetches the container by slug via fetchProject(), falling back
to the demo catalog, else notFound(). Page + generateMetadata made async (await params).

Also fix TemplateDetailBreadcrumb: it called server-only getTranslations while
rendered inside the client TemplateDetailContent tree (500 at request time) — switched
to the useTranslations hook. Was latent because demo pages were static-prerendered.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/[locale]/templates/[id]/page.tsx

@@ -2,24 +2,43 @@ import type { Metadata } from "next";
 import { notFound } from "next/navigation";
 
 import { TemplateDetailContent } from "@/components/templates/TemplateDetailContent";
-import { VIDEO_TEMPLATES_CATALOG } from "@/lib/video-templates-catalog";
+import { fetchProject } from "@/lib/admin-api";
+import {
+  adminProjectToCatalogTemplate,
+  VIDEO_TEMPLATES_CATALOG,
+  type VideoCatalogTemplate,
+} from "@/lib/video-templates-catalog";
 
 interface TemplateDetailPageProps {
-  params: { id: string };
+  params: Promise<{ id: string }>;
 }
 
+/**
+ * Resolve a template by its `[id]` route param — which is the container SLUG used
+ * in catalog links. Real (admin-managed) templates come from the content service
+ * via fetchProject(slug); the hardcoded demo catalog is the offline fallback.
+ */
+async function resolveTemplate(id: string): Promise<VideoCatalogTemplate | null> {
+  const admin = await fetchProject(id);
+  if (admin) return adminProjectToCatalogTemplate(admin);
+  return VIDEO_TEMPLATES_CATALOG.find((item) => item.id === id) ?? null;
+}
+
+// Pre-render the demo catalog; real container slugs render on demand (ISR).
 export function generateStaticParams() {
   return VIDEO_TEMPLATES_CATALOG.map((template) => ({ id: template.id }));
 }
 
-export function generateMetadata({ params }: TemplateDetailPageProps): Metadata {
-  const template = VIDEO_TEMPLATES_CATALOG.find((item) => item.id === params.id);
+export async function generateMetadata({ params }: TemplateDetailPageProps): Promise<Metadata> {
+  const { id } = await params;
+  const template = await resolveTemplate(id);
   if (!template) return {};
   return { title: `${template.name} — FlatRender` };
 }
 
-export default function TemplateDetailPage({ params }: TemplateDetailPageProps) {
-  const template = VIDEO_TEMPLATES_CATALOG.find((item) => item.id === params.id);
+export default async function TemplateDetailPage({ params }: TemplateDetailPageProps) {
+  const { id } = await params;
+  const template = await resolveTemplate(id);
   if (!template) notFound();
   return (
     <main className="min-h-screen bg-white">

src/components/templates/TemplateDetailBreadcrumb.tsx

@@ -1,15 +1,17 @@
+"use client";
+
 import Link from "next/link";
 import { ChevronRight } from "lucide-react";
-import { getTranslations } from "next-intl/server";
+import { useTranslations } from "next-intl";
 
 interface TemplateDetailBreadcrumbProps {
   templateName: string;
 }
 
-export async function TemplateDetailBreadcrumb({
+export function TemplateDetailBreadcrumb({
   templateName,
 }: TemplateDetailBreadcrumbProps) {
-  const t = await getTranslations("auto.componentsTemplatesTemplateDetailBreadcrumb");
+  const t = useTranslations("auto.componentsTemplatesTemplateDetailBreadcrumb");
 
   return (
     <nav aria-label={t("breadcrumbAriaLabel")} className="text-sm text-gray-500">