feat(reports): render generate-report form from OpenAPI spec

Replace hand-written GenerateReportPanel inputs with a generic loop over
extractFields("ReportQuery") + FormFieldRenderer; submit via
useResource("reports").create with server-side validation only.

react-openapi additions (all additive):
- lift items.enum into FieldConfig.enumValues for array-of-enum props
- extract schema `default` into FieldConfig.defaultValue
- new MultiEnumField renderer dispatched for isArray && enumValues
- FKFieldConfig.value: bind option values to a target property instead
  of the primary key (account names); sanitize-payload skips resolveFk
  when set
- new useFkFieldOptions hook encapsulating FK option loading/prefetch
- export extractFields, useFkFieldOptions, MultiEnumField

Drop now-unused granularityOptions/groupDimOptions helpers.

react-openapi/src/types.ts

@@ -85,6 +85,8 @@ export interface ResourceConfig {
 export interface FKFieldConfig {
   resource: string;
   prefetch: boolean;
+  /** Target property used as the wire value (defaults to the target's primary key). */
+  value?: string;
 }
 
 export interface OneOfOption {
@@ -106,6 +108,8 @@ export interface FieldConfig {
   readOnly: boolean;
   required: boolean;
   enumValues?: string[];
+  /** Schema-level `default` used to seed create-form state. */
+  defaultValue?: any;
   fk?: FKFieldConfig;
   uiType?: string;
   uploadUrl?: string;