feat: DEFAULT_LANGUAGE/DEFAULT_TIMEZONE config + public GET /api/config

crates/api/src/config.rs

@@ -0,0 +1,29 @@
+use axum::{Json, Router, extract::State, routing::get};
+use serde::Serialize;
+use utoipa::ToSchema;
+
+use crate::AppState;
+
+/// Public, non-sensitive instance configuration the SPA needs before login.
+#[derive(Serialize, ToSchema)]
+pub(crate) struct ConfigView {
+    /// User-facing product name.
+    pub app_name: String,
+    /// Default UI/content language (i18n key, e.g. "sv").
+    pub default_language: String,
+    /// Default display timezone (IANA name). Storage is UTC; this is a display hint.
+    pub default_timezone: String,
+}
+
+#[utoipa::path(get, path = "/api/config", responses((status = 200, body = ConfigView)))]
+pub(crate) async fn get_config(State(state): State<AppState>) -> Json<ConfigView> {
+    Json(ConfigView {
+        app_name: state.app_name.clone(),
+        default_language: state.default_language.clone(),
+        default_timezone: state.default_timezone.clone(),
+    })
+}
+
+pub(crate) fn routes() -> Router<AppState> {
+    Router::new().route("/api/config", get(get_config))
+}