feat(transcoding): add FFmpeg HLS transcoding support

- Introduced `TranscodeManager` for managing on-demand transcoding of local video files.
- Added configuration options for transcoding in `Config` and `LocalFilesConfig`.
- Implemented new API routes for managing transcoding settings, stats, and cache.
- Updated `LocalFilesProvider` to support transcoding capabilities.
- Created frontend components for managing transcode settings and displaying stats.
- Added database migration for transcode settings.
- Enhanced existing routes and DTOs to accommodate new transcoding features.

k-tv-backend/api/src/main.rs

@@ -75,6 +75,10 @@ async fn main() -> anyhow::Result<()> {
     // Build provider registry — all configured providers are registered simultaneously.
     #[cfg(feature = "local-files")]
     let mut local_index: Option<Arc<infra::LocalIndex>> = None;
+    #[cfg(feature = "local-files")]
+    let mut transcode_manager: Option<Arc<infra::TranscodeManager>> = None;
+    #[cfg(feature = "local-files")]
+    let mut sqlite_pool_for_state: Option<sqlx::SqlitePool> = None;
 
     let mut registry = infra::ProviderRegistry::new();
 
@@ -99,12 +103,41 @@ async fn main() -> anyhow::Result<()> {
             let lf_cfg = infra::LocalFilesConfig {
                 root_dir: dir.clone(),
                 base_url: config.base_url.clone(),
+                transcode_dir: config.transcode_dir.clone(),
+                cleanup_ttl_hours: config.transcode_cleanup_ttl_hours,
             };
             let idx = Arc::new(infra::LocalIndex::new(&lf_cfg, sqlite_pool.clone()).await);
             local_index = Some(Arc::clone(&idx));
             let scan_idx = Arc::clone(&idx);
             tokio::spawn(async move { scan_idx.rescan().await; });
-            registry.register("local", Arc::new(infra::LocalFilesProvider::new(idx, lf_cfg)));
+
+            // Build TranscodeManager if TRANSCODE_DIR is set.
+            let tm = config.transcode_dir.as_ref().map(|td| {
+                std::fs::create_dir_all(td).ok();
+                tracing::info!("Transcoding enabled; cache dir: {:?}", td);
+                let tm = infra::TranscodeManager::new(td.clone(), config.transcode_cleanup_ttl_hours);
+                // Load persisted TTL from DB.
+                let tm_clone = Arc::clone(&tm);
+                let pool_clone = sqlite_pool.clone();
+                tokio::spawn(async move {
+                    if let Ok(row) = sqlx::query_as::<_, (i64,)>(
+                        "SELECT cleanup_ttl_hours FROM transcode_settings WHERE id = 1",
+                    )
+                    .fetch_one(&pool_clone)
+                    .await
+                    {
+                        tm_clone.set_cleanup_ttl(row.0 as u32);
+                    }
+                });
+                tm
+            });
+
+            registry.register(
+                "local",
+                Arc::new(infra::LocalFilesProvider::new(idx, lf_cfg, tm.clone())),
+            );
+            transcode_manager = tm;
+            sqlite_pool_for_state = Some(sqlite_pool.clone());
         } else {
             tracing::warn!("local-files requires SQLite; ignoring LOCAL_FILES_DIR");
         }
@@ -137,6 +170,8 @@ async fn main() -> anyhow::Result<()> {
     #[cfg(feature = "local-files")]
     {
         state.local_index = local_index;
+        state.transcode_manager = transcode_manager;
+        state.sqlite_pool = sqlite_pool_for_state;
     }
 
     let server_config = ServerConfig {
@@ -206,6 +241,7 @@ impl IMediaProvider for NoopMediaProvider {
             search: false,
             streaming_protocol: StreamingProtocol::DirectFile,
             rescan: false,
+            transcode: false,
         }
     }