Custom add and create flow polish

lib/create/methodCardCustomizeMetaPatch.ts

@@ -0,0 +1,19 @@
+import type { CreateFlowState } from "../../app/(app)/create/types";
+import type { MethodCardHeaderDraft } from "./methodCardCustomizeSession";
+
+/**
+ * Merges edited customize header strings into persisted method-card meta.
+ */
+export function methodCardMetaWithCustomizeHeader(
+  existing: CreateFlowState["customMethodCardMetaById"],
+  pendingCardId: string,
+  header: MethodCardHeaderDraft,
+): NonNullable<CreateFlowState["customMethodCardMetaById"]> {
+  return {
+    ...(existing ?? {}),
+    [pendingCardId]: {
+      label: header.title,
+      supportText: header.description,
+    },
+  };
+}