domain ports: CQRS-split traits for all bounded contexts

crates/domain/src/ports/settings.rs

@@ -0,0 +1,21 @@
+//! Application settings port.
+//!
+//! Key-value admin configuration (e.g. `library_sync_interval_hours`).
+//! Small enough to keep as a single trait rather than CQRS split.
+
+use async_trait::async_trait;
+
+use crate::errors::DomainResult;
+
+/// Port for general admin settings persistence (`app_settings` table).
+#[async_trait]
+pub trait AppSettingsRepository: Send + Sync {
+    /// Get a setting value by key. Returns `None` if not set.
+    async fn get(&self, key: &str) -> DomainResult<Option<String>>;
+
+    /// Set a setting value (upsert).
+    async fn set(&self, key: &str, value: &str) -> DomainResult<()>;
+
+    /// Get all settings as (key, value) pairs.
+    async fn get_all(&self) -> DomainResult<Vec<(String, String)>>;
+}