feat: enable patient form interactions and revision-aware signing

patient-h5/src/types/signing.ts

@@ -1,5 +1,6 @@
 import type {
   SignDeliveryChannel,
+  SigningFormState,
   SignatureFieldPosition,
   SignatureUploadResponse,
   SigningContextField,
@@ -37,6 +38,9 @@ export interface SignFlowState {
   contentSha256: string
   /** 医生已填的结果（含医师签名图），患者端**只读**渲染 */
   staffAnswers: Record<string, string>
+  form: SigningFormState | null
+  formSaving: boolean
+  formError: string
   /** 患者端可交互的字段。按约定只有主签名位（`id === 'signature'`） */
   fields: SigningContextField[]
   /** PDF points and page number supplied by the task's frozen template version. */