Migration Angular 20 -> 21 : fin de la migration securite (0 vulnerabilite npm)

- ng update @angular/core@21 @angular/cli@21 (corrige GHSA-jrmj-c5cx-3cw6, XSS SVG)
- Migration automatique des templates vers le control flow natif (@if/@for, 138 fichiers)
- Correction des 5 `track` invalides generes par la migration (trackBy a 1 argument
  -> track $index) + suppression des fonctions trackBy mortes
- TypeScript 5.9, zone.js 0.15 ; npm audit : 0 vulnerabilite

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/app/campaigns/character/character-view/character-view.component.html

@@ -5,10 +5,12 @@
       Retour
     </button>
     <span class="spacer"></span>
-    <button class="btn-ai" (click)="toggleChat()" [class.active]="chatOpen" *ngIf="characterId">
-      <lucide-icon [img]="Sparkles" [size]="14"></lucide-icon>
-      Assistant IA
-    </button>
+    @if (characterId) {
+      <button class="btn-ai" (click)="toggleChat()" [class.active]="chatOpen">
+        <lucide-icon [img]="Sparkles" [size]="14"></lucide-icon>
+        Assistant IA
+      </button>
+    }
     <button class="btn-edit" (click)="edit()">
       <lucide-icon [img]="Edit3" [size]="14"></lucide-icon>
       Editer
@@ -18,11 +20,12 @@
   <app-persona-view [persona]="character" [templateFields]="templateFields"></app-persona-view>
 </div>
 
-<app-ai-chat-drawer
-  *ngIf="characterId && campaignId"
-  [campaignId]="campaignId"
-  entityType="character"
-  [entityId]="characterId"
-  [isOpen]="chatOpen"
-  (close)="chatOpen = false">
-</app-ai-chat-drawer>
+@if (characterId && campaignId) {
+  <app-ai-chat-drawer
+    [campaignId]="campaignId"
+    entityType="character"
+    [entityId]="characterId"
+    [isOpen]="chatOpen"
+    (close)="chatOpen = false">
+  </app-ai-chat-drawer>
+}