refactor: replace get_stream_url with get_source_uri per ADR-0002

Providers now expose a source URI (for FFmpeg) instead of a
viewer-facing stream URL. Playout Service will own transcoding.

- Add SourceUri value object (NetworkUrl | FilePath)
- Remove StreamQuality, StreamingProtocol from domain
- Simplify ProviderCapabilities (drop streaming_protocol, transcode)
- Jellyfin: return static direct stream URL
- Local files: return absolute file path
- Rename use case get_stream_url -> get_source
- Stream endpoint returns JSON SourceUri instead of 307 redirect

crates/application/src/schedule/mod.rs

@@ -3,9 +3,9 @@ pub mod deps;
 pub mod generate;
 pub mod get_current_broadcast;
 pub mod get_epg;
-pub mod get_stream_url;
+pub mod get_source;
 pub mod queries;
 
 pub use commands::GenerateScheduleCommand;
 pub use deps::ScheduleDeps;
-pub use queries::{GetCurrentBroadcastQuery, GetEpgQuery, GetStreamUrlQuery};
+pub use queries::{GetCurrentBroadcastQuery, GetEpgQuery, GetSourceQuery};