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/commands.rs

@@ -0,0 +1,32 @@
+use uuid::Uuid;
+
+use domain::models::ScheduleConfig;
+use domain::value_objects::RecyclePolicy;
+
+/// Create a new channel.
+pub struct CreateChannelCommand {
+    pub owner_id: Uuid,
+    pub name: String,
+    pub timezone: String,
+}
+
+/// Update an existing channel (partial — only `Some` fields are applied).
+pub struct UpdateChannelCommand {
+    pub channel_id: Uuid,
+    /// Used for ownership check.
+    pub owner_id: Uuid,
+    pub name: Option<String>,
+    /// `Some(None)` clears the description; `None` leaves it unchanged.
+    pub description: Option<Option<String>>,
+    pub timezone: Option<String>,
+    pub schedule_config: Option<ScheduleConfig>,
+    pub recycle_policy: Option<RecyclePolicy>,
+    pub auto_schedule: Option<bool>,
+}
+
+/// Delete a channel.
+pub struct DeleteChannelCommand {
+    pub channel_id: Uuid,
+    /// Used for ownership check.
+    pub owner_id: Uuid,
+}