Custom add and create flow polish

lib/create/usesWizardFieldBlocksModalBody.ts

@@ -0,0 +1,49 @@
+import type { CreateFlowState } from "../../app/(app)/create/types";
+import type { CustomMethodCardFieldBlock } from "./customMethodCardFieldBlocks";
+import { isCustomMethodCardId } from "./isCustomMethodCardId";
+
+/**
+ * Create modals use {@link CustomMethodCardModalBody} when there are structured field
+ * blocks for this method id (wizard-finalized cards, final-review chip edits, etc.),
+ * including **proportion-only** layouts.
+ *
+ * Check persisted blocks **before** {@link isCustomMethodCardId}: `meta` can be absent
+ * while `customMethodCardFieldBlocksById[id]` is still populated (e.g. partial merges).
+ *
+ * Duplicating a preset registers `meta` for the clone but leaves blocks empty — those
+ * stubs keep the facet's structured edit fields until the user adds blocks (then this
+ * returns true once persisted blocks are non-empty).
+ *
+ * **View mode** (`modalEditUnlocked` false): when the custom card still has facet copy
+ * that matches preset seeds only (see `./methodCardFacetMatchesPresetForId`), route to
+ * {@link CustomMethodCardModalBody} so meta-only wizard cards show policy copy instead
+ * of empty preset section editors. Pass `customFacetDetailsMatchPreset: false` when the
+ * caller knows facet details were edited or cloned from a filled preset.
+ */
+export function usesWizardFieldBlocksModalBody(args: {
+  methodId: string;
+  meta: CreateFlowState["customMethodCardMetaById"];
+  fieldBlocksById: CreateFlowState["customMethodCardFieldBlocksById"];
+  modalEditUnlocked: boolean;
+  draftFieldBlocks: readonly CustomMethodCardFieldBlock[] | null;
+  /** When strictly `true` and modal is read-only, use wizard body for custom cards with empty blocks. */
+  customFacetDetailsMatchPreset?: boolean;
+}): boolean {
+  const persisted = args.fieldBlocksById?.[args.methodId];
+  if (Array.isArray(persisted) && persisted.length > 0) {
+    return true;
+  }
+  if (!isCustomMethodCardId(args.methodId, args.meta)) {
+    return false;
+  }
+  if (
+    args.modalEditUnlocked &&
+    args.draftFieldBlocks !== null &&
+    args.draftFieldBlocks.length > 0
+  ) {
+    return true;
+  }
+  return (
+    !args.modalEditUnlocked && args.customFacetDetailsMatchPreset === true
+  );
+}