feat: systeme de tickets utilisateur connecte a Gitea

Formulaire de suggestions/signalements (utilisateur connecte) qui cree une
issue dans le depot Gitea via son API v1 :
- GiteaIssueService (appel API), SuggestionController (validation + creation)
- vue suggestions/create au style DSFR, lien dans la sidebar (@auth)
- config services.gitea + variables GITEA_URL/TOKEN/REPO
- tests de bout en bout (auth, validation, appel API mocke)

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

WEB/resources/views/layouts/sidebar.blade.php

@@ -50,6 +50,18 @@
             Guides & Informations
         </a>
 
+        <!-- Signaler / Suggérer (utilisateur connecté → ticket Gitea) -->
+        @auth
+        <a href="{{ route('suggestions.create') }}"
+           class="flex items-center gap-4 px-4 py-3 rounded-sm transition-all group {{ request()->routeIs('suggestions.*') ? 'text-white bg-[#000091] font-bold shadow-md' : 'text-slate-700 hover:bg-slate-50 font-medium border-b border-slate-100/50' }}"
+           {!! request()->routeIs('suggestions.*') ? 'aria-current="page"' : '' !!}>
+            <div class="w-8 h-8 rounded-sm flex items-center justify-center transition-colors {{ request()->routeIs('suggestions.*') ? 'bg-white/20 text-white' : 'bg-green-50 text-[--cz-jade]' }}" aria-hidden="true">
+                <x-heroicon-o-chat-bubble-left-right class="h-4 w-4" />
+            </div>
+            Signaler / Suggérer
+        </a>
+        @endauth
+
         <div class="pt-10 space-y-1">
             <p class="text-[10px] font-bold text-slate-500 uppercase tracking-[0.2em] mb-4 px-4">Services de l'État</p>
             <a href="#" class="flex items-center justify-between px-4 py-2 text-sm text-slate-600 hover:text-[--fr-blue] font-medium transition-colors">