feat: add system configuration API endpoint and frontend hook for dynamic settings

notes-api/src/dto.rs

@@ -166,3 +166,9 @@ impl From<notes_domain::NoteVersion> for NoteVersionResponse {
         }
     }
 }
+
+/// System configuration response
+#[derive(Debug, Serialize)]
+pub struct ConfigResponse {
+    pub allow_registration: bool,
+}

notes-api/src/routes/config.rs

@@ -0,0 +1,14 @@
+//! Configuration routes
+
+use axum::{Json, extract::State};
+
+use crate::dto::ConfigResponse;
+use crate::error::ApiResult;
+use crate::state::AppState;
+
+/// Get system configuration
+pub async fn get_config(State(state): State<AppState>) -> ApiResult<Json<ConfigResponse>> {
+    Ok(Json(ConfigResponse {
+        allow_registration: state.config.allow_registration,
+    }))
+}

notes-api/src/routes/mod.rs

@@ -1,6 +1,7 @@
 //! Route definitions and module structure
 
 pub mod auth;
+pub mod config;
 pub mod import_export;
 pub mod notes;
 pub mod tags;
@@ -40,4 +41,6 @@ pub fn api_v1_router() -> Router<AppState> {
             "/tags/{id}",
             delete(tags::delete_tag).patch(tags::rename_tag),
         )
+        // System Config
+        .route("/config", get(config::get_config))
 }