feat: implement find_all method in ChannelRepository and update related services and routes for public access

k-tv-backend/domain/src/repositories.rs

@@ -36,6 +36,7 @@ pub trait UserRepository: Send + Sync {
 pub trait ChannelRepository: Send + Sync {
     async fn find_by_id(&self, id: ChannelId) -> DomainResult<Option<Channel>>;
     async fn find_by_owner(&self, owner_id: UserId) -> DomainResult<Vec<Channel>>;
+    async fn find_all(&self) -> DomainResult<Vec<Channel>>;
     /// Insert or update a channel.
     async fn save(&self, channel: &Channel) -> DomainResult<()>;
     async fn delete(&self, id: ChannelId) -> DomainResult<()>;