feat: L'Ami Fiduciaire V1.0.0 — full codebase with Story 0.1 complete

Initial commit of the L'Ami Fiduciaire SaaS platform built on Laravel 12,
Vue 3, Inertia.js 2, and Tailwind CSS 4.

Story 0.1 (rename folders to declarations in database) is implemented and
code-reviewed: migration, rollback, and 6 Pest tests all passing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Notifications/FolderMentionNotification.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace App\Notifications;
+
+use App\Models\Folder;
+use App\Models\User;
+use Illuminate\Bus\Queueable;
+use Illuminate\Contracts\Queue\ShouldQueue;
+use Illuminate\Notifications\Messages\MailMessage;
+use Illuminate\Notifications\Notification;
+
+class FolderMentionNotification extends Notification implements ShouldQueue
+{
+    use Queueable;
+
+    public function __construct(
+        public Folder $folder,
+        public User $mentionedBy,
+        public string $message,
+    ) {}
+
+    /**
+     * @return array<string>
+     */
+    public function via(object $notifiable): array
+    {
+        return ['database', 'mail'];
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function toDatabase(object $notifiable): array
+    {
+        return [
+            'folder_id' => $this->folder->id,
+            'folder_title' => $this->folder->title,
+            'mentioned_by_id' => $this->mentionedBy->id,
+            'mentioned_by_name' => $this->mentionedBy->name,
+            'message' => $this->message,
+            'url' => route('folders.show', $this->folder),
+        ];
+    }
+
+    public function toMail(object $notifiable): MailMessage
+    {
+        return (new MailMessage)
+            ->subject('Vous avez été mentionné - '.$this->folder->title)
+            ->markdown('emails.folder-mention', [
+                'folderTitle' => $this->folder->title,
+                'mentionedByName' => $this->mentionedBy->name,
+                'message' => $this->message,
+                'url' => route('folders.show', $this->folder),
+            ]);
+    }
+}