RuleTemplate seed and create flow

lib/create/fetchTemplates.ts

@@ -0,0 +1,45 @@
+/**
+ * Client fetch for curated rule templates (GET /api/templates).
+ */
+
+export type RuleTemplateDto = {
+  id: string;
+  slug: string;
+  title: string;
+  category: string | null;
+  description: string | null;
+  body: unknown;
+  featured: boolean;
+};
+
+type TemplatesResponse = { templates?: RuleTemplateDto[] };
+
+export async function fetchTemplates(): Promise<
+  RuleTemplateDto[] | { error: string }
+> {
+  try {
+    const res = await fetch("/api/templates", { credentials: "include" });
+    const data = (await res.json()) as TemplatesResponse & { error?: string };
+    if (!res.ok) {
+      return {
+        error:
+          typeof data.error === "string"
+            ? data.error
+            : "Could not load templates",
+      };
+    }
+    return Array.isArray(data.templates) ? data.templates : [];
+  } catch {
+    return { error: "Could not load templates" };
+  }
+}
+
+export async function fetchTemplateBySlug(
+  slug: string,
+): Promise<RuleTemplateDto | null | { error: string }> {
+  const result = await fetchTemplates();
+  if ("error" in result) {
+    return result;
+  }
+  return result.find((t) => t.slug === slug) ?? null;
+}