Formulaire public : encart de paiement de la cotisation via Yapla

FormTemplate.yapla_url (lien vers la page de cotisation Yapla, doit
commencer par http(s)://, PATCH .../form comme description/is_open)
fait apparaître un encart « Payer ma cotisation » sous la case
WILLING_TO_PAY_FEE, sur le formulaire public. Configurable depuis le
panneau « Personnalisation » de l'écran /inscriptions. La case reste
une simple déclaration : rien ne vérifie que le paiement a eu lieu.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/api/mock/dataset.ts

@@ -56,6 +56,7 @@ export interface MockState {
     logo: string | null; // data URL
     logoType: string | null;
     description: string | null;
+    yaplaUrl: string | null;
   };
   /** volunteerId -> photo (formulaire public), data URL. */
   photos: Map<string, string>;
@@ -445,7 +446,9 @@ export function buildMockState(): MockState {
       backImageType: null,
       fields: [],
     },
-    formTemplate: { isOpen: true, fields: [], logo: null, logoType: null, description: null },
+    formTemplate: {
+      isOpen: true, fields: [], logo: null, logoType: null, description: null, yaplaUrl: null,
+    },
     photos: new Map(),
     seq,
   };

frontend/src/api/mock/mock-client.ts

@@ -128,6 +128,7 @@ const formTemplateRead = (): FormTemplateRead => ({
   fields: state.formTemplate.fields,
   has_logo: state.formTemplate.logo !== null,
   description: state.formTemplate.description,
+  yapla_url: state.formTemplate.yaplaUrl,
 });
 
 // PDF valide minimal (une page blanche) — remplace la vraie génération
@@ -1483,6 +1484,12 @@ export function createMockApi(): PlanningApi {
       setOpen: (_edition, body: FormTemplateUpdate) => {
         if (body.is_open !== undefined) state.formTemplate.isOpen = body.is_open;
         if (body.description !== undefined) state.formTemplate.description = body.description;
+        if (body.yapla_url !== undefined) {
+          if (body.yapla_url && !/^https?:\/\//.test(body.yapla_url)) {
+            throw new ApiError(422, 'form.invalid_yapla_url');
+          }
+          state.formTemplate.yaplaUrl = body.yapla_url;
+        }
         return delay<FormTemplateRead>(formTemplateRead());
       },
       uploadLogo: async (_edition, file: File) => {
@@ -1511,6 +1518,7 @@ export function createMockApi(): PlanningApi {
             : [],
           has_logo: state.formTemplate.logo !== null,
           description: state.formTemplate.description,
+          yapla_url: state.formTemplate.yaplaUrl,
         });
       },
       submitPublic: async (_edition, body: PublicFormSubmission) => {

frontend/src/api/schema.ts

@@ -573,12 +573,14 @@ export interface FormTemplateRead {
   fields: FormFieldType[];
   has_logo: boolean;
   description: string | null;
+  yapla_url: string | null;
 }
 
 /** `undefined`/absent = inchangé pour chaque champ. */
 export interface FormTemplateUpdate {
   is_open?: boolean;
   description?: string | null;
+  yapla_url?: string | null;
 }
 
 export interface PublicPositionOption {
@@ -600,6 +602,7 @@ export interface PublicFormConfig {
   artists: PublicArtistOption[];
   has_logo: boolean;
   description: string | null;
+  yapla_url: string | null;
 }
 
 export interface FormSubmissionResult {