feat(front) : ajustements layout maquette (sidebar, marges, titres)

- sidebar deplie a 232px (repli 72px conserve)
- marge horizontale du contenu responsive, 170px des xl (1280px)
- gap navbar -> contenu de 47px
- composant partage PageHeader (titre 32px/600, marge basse 44px, slot actions)
- migration des 6 pages vers PageHeader, suppression des marges hautes redondantes

frontend/app/layouts/default.vue

@@ -4,6 +4,7 @@
             <MalioSidebar
                 v-model="ui.sidebarCollapsed"
                 :sections="translatedSections"
+                :sidebar-class="ui.sidebarCollapsed ? '' : 'w-[232px]'"
             >
                 <template #logo>
                     <img src="/LOGO_MALIO.png" alt="Malio"/>
@@ -16,10 +17,10 @@
             <div class="h-full flex-1 flex flex-col min-h-0 min-w-0">
                 <SiteSelector v-if="showSiteSelector"/>
                 <main
-                    class="flex flex-1 flex-col overflow-y-auto overflow-x-hidden bg-white px-4 pb-24 sm:px-8 lg:px-16">
+                    class="flex flex-1 flex-col overflow-y-auto overflow-x-hidden bg-white px-4 pb-10 sm:px-6 lg:px-12 xl:px-[170px]">
                     <div
                         aria-hidden="true"
-                        class="pointer-events-none sticky top-0 z-30 h-8 flex-shrink-0 bg-white sm:h-12"/>
+                        class="pointer-events-none sticky top-0 z-30 h-[47px] flex-shrink-0 bg-white"/>
                     <slot/>
                 </main>
             </div>