chore : ajouter fichiers non versionnés (migrations SQL, 404, PROJET.md)

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

database/migration_013_profiles.sql

@@ -0,0 +1,9 @@
+CREATE TABLE IF NOT EXISTS profiles (
+    id          SERIAL PRIMARY KEY,
+    slug        TEXT    NOT NULL UNIQUE,
+    label       TEXT    NOT NULL DEFAULT '',
+    description TEXT,
+    permissions JSONB   NOT NULL DEFAULT '[]',
+    is_system   BOOLEAN NOT NULL DEFAULT FALSE,
+    is_active   BOOLEAN NOT NULL DEFAULT TRUE
+);