feat: add server-sent events for logging and activity tracking

- Implemented a custom tracing layer (`AppLogLayer`) to capture log events and broadcast them to SSE clients.
- Created admin routes for streaming server logs and listing recent activity logs.
- Added an activity log repository interface and SQLite implementation for persisting activity events.
- Integrated activity logging into user authentication and channel CRUD operations.
- Developed frontend components for displaying server logs and activity logs in the admin panel.
- Enhanced the video player with a stats overlay for monitoring streaming metrics.

k-tv-backend/infra/src/factory.rs

@@ -1,7 +1,7 @@
 use std::sync::Arc;
 
 use crate::db::DatabasePool;
-use domain::{ChannelRepository, ScheduleRepository, UserRepository};
+use domain::{ActivityLogRepository, ChannelRepository, ScheduleRepository, UserRepository};
 
 #[derive(Debug, thiserror::Error)]
 pub enum FactoryError {
@@ -51,6 +51,25 @@ pub async fn build_channel_repository(
     }
 }
 
+pub async fn build_activity_log_repository(
+    pool: &DatabasePool,
+) -> FactoryResult<Arc<dyn ActivityLogRepository>> {
+    match pool {
+        #[cfg(feature = "sqlite")]
+        DatabasePool::Sqlite(pool) => Ok(Arc::new(
+            crate::activity_log_repository::SqliteActivityLogRepository::new(pool.clone()),
+        )),
+        #[cfg(feature = "postgres")]
+        DatabasePool::Postgres(_pool) => Err(FactoryError::NotImplemented(
+            "ActivityLogRepository not yet implemented for Postgres".to_string(),
+        )),
+        #[allow(unreachable_patterns)]
+        _ => Err(FactoryError::NotImplemented(
+            "No database feature enabled".to_string(),
+        )),
+    }
+}
+
 pub async fn build_schedule_repository(
     pool: &DatabasePool,
 ) -> FactoryResult<Arc<dyn ScheduleRepository>> {