feat: bloc About avec versions dans les settings

- Endpoint GET /version (sans auth) retournant la version API
- Bloc About dans l'onglet General : nom du projet, description,
  versions API et Backoffice, lien GitHub

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/src/handlers.rs

@@ -7,6 +7,12 @@ pub async fn health() -> &'static str {
     "ok"
 }
 
+pub async fn version() -> Json<serde_json::Value> {
+    Json(serde_json::json!({
+        "api": env!("CARGO_PKG_VERSION"),
+    }))
+}
+
 pub async fn docs_redirect() -> impl axum::response::IntoResponse {
     axum::response::Redirect::to("/swagger-ui/")
 }

apps/api/src/main.rs

@@ -199,6 +199,7 @@ async fn main() -> anyhow::Result<()> {
 
     let app = Router::new()
         .route("/health", get(handlers::health))
+        .route("/version", get(handlers::version))
         .route("/ready", get(handlers::ready))
         .route("/metrics", get(handlers::metrics))
         .route("/docs", get(handlers::docs_redirect))