application: channels bounded context

CQRS use cases (create/update/delete/get/list/list_by_owner),
ownership checks, auto-snapshot on config change.
Channel setters added to domain model.

crates/application/src/channels/deps.rs

@@ -0,0 +1,15 @@
+use std::sync::Arc;
+
+use domain::ports::{ChannelCommand, ChannelQuery, EventPublisher};
+
+/// Dependencies for channel write use cases (create, update, delete).
+pub struct ChannelCommandDeps {
+    pub channel_command: Arc<dyn ChannelCommand>,
+    pub channel_query: Arc<dyn ChannelQuery>,
+    pub event_publisher: Arc<dyn EventPublisher>,
+}
+
+/// Dependencies for channel read use cases (get, list, list_by_owner).
+pub struct ChannelQueryDeps {
+    pub channel_query: Arc<dyn ChannelQuery>,
+}