fix(frontend): navigation cohérente entre les pages authentifiées

Logo cliquable vers le tableau de bord (ev-brand-link) et fil d'Ariane
(ev-breadcrumb) sur les sous-pages, pour éviter les impasses de
navigation entre dashboard, liste des sites et détail de site.

apps/frontend/src/app/features/dashboard/dashboard.html

@@ -1,14 +1,16 @@
 <div class="dashboard">
   <header class="dashboard__header">
     <div class="dashboard__brand">
-      <ev-brand class="dashboard__logo" />
+      <a routerLink="/dashboard" class="ev-brand-link">
+        <ev-brand class="dashboard__logo" />
+      </a>
       <div>
         <h1>Vue d'ensemble</h1>
         <p class="dashboard__subtitle">Consommation instantanée du parc</p>
       </div>
     </div>
     <div class="dashboard__actions">
-      <a routerLink="/sites" class="dashboard__sites-link">Voir les sites</a>
+      <a routerLink="/sites" class="ev-link">Voir les sites</a>
       <ev-button
         class="logout-button"
         variant="secondary"

apps/frontend/src/app/features/dashboard/dashboard.scss

@@ -40,16 +40,6 @@
   gap: 1rem;
 }
 
-.dashboard__sites-link {
-  color: var(--color-primary);
-  font-weight: 600;
-  text-decoration: none;
-
-  &:hover {
-    text-decoration: underline;
-  }
-}
-
 h2 {
   font-size: 1.1rem;
   font-weight: 600;

apps/frontend/src/app/features/sites/site-detail-placeholder/site-detail-placeholder.html

@@ -1,5 +1,19 @@
 <div class="site-detail-placeholder">
+  <nav class="ev-breadcrumb">
+    <a routerLink="/dashboard">Tableau de bord</a>
+    <span>/</span>
+    <a routerLink="/sites">Sites</a>
+  </nav>
+
+  <header class="site-detail-placeholder__header">
+    <a routerLink="/dashboard" class="ev-brand-link">
+      <ev-brand class="site-detail-placeholder__logo" />
+    </a>
+    <h1>Site {{ siteId }}</h1>
+  </header>
+
   <ev-card>
-    <p>Détail du site {{ siteId }} : à venir (voir issue #51).</p>
+    <p>Le détail de ce site est à venir (voir issue #51).</p>
+    <a routerLink="/sites" class="ev-link">Retour aux sites</a>
   </ev-card>
 </div>

apps/frontend/src/app/features/sites/site-detail-placeholder/site-detail-placeholder.scss

@@ -1,6 +1,28 @@
 :host {
   display: block;
+  color: var(--color-text);
   padding: 2.5rem 2rem;
   max-width: 640px;
   margin: 0 auto;
 }
+
+.site-detail-placeholder__header {
+  display: flex;
+  align-items: center;
+  gap: 0.85rem;
+  margin-bottom: 1.5rem;
+
+  h1 {
+    margin: 0;
+    font-size: 1.5rem;
+    font-weight: 700;
+  }
+}
+
+.site-detail-placeholder__logo {
+  font-size: 1.3rem;
+}
+
+ev-card p {
+  margin: 0 0 0.75rem;
+}

apps/frontend/src/app/features/sites/site-detail-placeholder/site-detail-placeholder.spec.ts

@@ -1,5 +1,5 @@
 import { TestBed } from '@angular/core/testing';
-import { ActivatedRoute, convertToParamMap } from '@angular/router';
+import { ActivatedRoute, convertToParamMap, provideRouter } from '@angular/router';
 import { SiteDetailPlaceholder } from './site-detail-placeholder';
 
 describe('SiteDetailPlaceholder', () => {
@@ -7,6 +7,7 @@ describe('SiteDetailPlaceholder', () => {
     TestBed.configureTestingModule({
       imports: [SiteDetailPlaceholder],
       providers: [
+        provideRouter([]),
         {
           provide: ActivatedRoute,
           useValue: { snapshot: { paramMap: convertToParamMap({ siteId: 'SITE001' }) } },

apps/frontend/src/app/features/sites/site-detail-placeholder/site-detail-placeholder.ts

@@ -1,11 +1,12 @@
 import { Component, inject } from '@angular/core';
-import { ActivatedRoute } from '@angular/router';
+import { ActivatedRoute, RouterLink } from '@angular/router';
 import { Card } from '../../../shared/components/ui/card/card';
+import { Brand } from '../../../shared/components/ui/brand/brand';
 
 @Component({
   selector: 'app-site-detail-placeholder',
   standalone: true,
-  imports: [Card],
+  imports: [RouterLink, Card, Brand],
   templateUrl: './site-detail-placeholder.html',
   styleUrl: './site-detail-placeholder.scss',
 })

apps/frontend/src/app/features/sites/site-list/site-list.html

@@ -1,6 +1,12 @@
 <div class="site-list">
+  <nav class="ev-breadcrumb">
+    <a routerLink="/dashboard">Tableau de bord</a>
+  </nav>
+
   <header class="site-list__header">
-    <ev-brand class="site-list__logo" />
+    <a routerLink="/dashboard" class="ev-brand-link">
+      <ev-brand class="site-list__logo" />
+    </a>
     <div>
       <h1>Sites</h1>
       <p class="site-list__subtitle">Vue d'ensemble du parc suivi</p>