Remove the build credit from the footer

Drops "Hecho con Angular, Analog y Nx." and the API link beside it,
leaving the copyright line on its own.

`footer.built` goes with it in all three locales. So does `footer.api`,
which was already dead -- declared and translated, never rendered.

The row's flex and space-between existed only to push the credit to the
far end, so they go too.

Verified in es/en/ca: no trace of the credit or the docs link in the
served HTML, and the copyright line renders in each.

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

landing/src/app/core/copy.ts

@@ -89,7 +89,7 @@ export interface Copy {
     error: string;
     closed: string;
   };
-  footer: { built: string; api: string; rights: string };
+  footer: { rights: string };
   maintenance: { title: string; back: string; until: string };
 }
 
@@ -180,8 +180,6 @@ const es: Copy = {
     closed: 'El formulario está cerrado temporalmente.',
   },
   footer: {
-    built: 'Hecho con Angular, Analog y Nx.',
-    api: 'Contenido servido por la API pública de Pireon.',
     rights: 'Todos los derechos reservados.',
   },
   maintenance: {
@@ -278,8 +276,6 @@ const en: Copy = {
     closed: 'The form is temporarily closed.',
   },
   footer: {
-    built: 'Built with Angular, Analog and Nx.',
-    api: 'Content served by the Pireon public API.',
     rights: 'All rights reserved.',
   },
   maintenance: {
@@ -376,8 +372,6 @@ const ca: Copy = {
     closed: 'El formulari està tancat temporalment.',
   },
   footer: {
-    built: 'Fet amb Angular, Analog i Nx.',
-    api: 'Contingut servit per l’API pública de Pireon.',
     rights: 'Tots els drets reservats.',
   },
   maintenance: {