docs: migrer schémas BDD de Mermaid vers DBML

Remplace les diagrammes Mermaid par DBML (via kroki-dbml) pour
une meilleure expressivité des schémas de base de données :
- Ajout support notes, contraintes et indexes détaillés
- Migration de tous les schémas d'entités partagées
- Ajout fichier exemple dbml-example.md
- Configuration plugin mkdocs-kroki pour rendu DBML

docs/domains/_shared/entities/devices.md

@@ -4,26 +4,43 @@
 
 ## Diagramme
 
-```mermaid
-erDiagram
-    USERS ||--o{ DEVICES : "possède"
-    DEVICES ||--o{ SESSIONS : "a"
+```kroki-dbml
+Table users {
+  id uuid [primary key]
+}
 
-    DEVICES {
-        uuid id PK
-        uuid user_id FK
-        string device_name
-        string os
-        string browser
-        string device_type
-        boolean is_trusted
-        timestamp trusted_until
-        timestamp first_seen_at
-        timestamp last_seen_at
-        inet last_ip
-        string last_city
-        string last_country_code
-    }
+Table devices {
+  id uuid [primary key]
+  user_id uuid [not null, ref: > users.id]
+  device_name varchar(255) [note: 'User-defined device name']
+  os varchar(50) [note: 'iOS, Android, Windows, macOS, Linux']
+  browser varchar(50) [note: 'Safari, Chrome, Firefox, etc.']
+  device_type device_type_enum [not null, note: 'mobile, tablet, desktop, car']
+  is_trusted boolean [not null, default: false, note: 'Bypass 2FA for 30 days if true']
+  trusted_until timestamp [note: 'NULL if not trusted, expires after 30 days']
+  first_seen_at timestamp [not null, default: `now()`]
+  last_seen_at timestamp [not null, default: `now()`]
+  last_ip inet [not null]
+  last_city varchar(100)
+  last_country_code char(2)
+
+  indexes {
+    (user_id, last_seen_at) [note: 'List user devices by recent activity']
+    (user_id, is_trusted) [note: 'Find trusted devices for user']
+  }
+}
+
+Table sessions {
+  id uuid [primary key]
+  device_id uuid [ref: > devices.id]
+}
+
+Enum device_type_enum {
+  mobile [note: 'Smartphone Android/iOS']
+  tablet [note: 'Tablette']
+  desktop [note: 'Ordinateur']
+  car [note: 'Système embarqué (CarPlay/Android Auto)']
+}
 ```
 
 ## Légende