feat: add CLI args, health endpoint, and fix torznab search

- Add clap for CLI argument parsing (-c config, -p port)
- Add health endpoint showing service status at /api/health
- Add IndexerType enum for auto URL construction (jackett/prowlarr/torznab)
- Fix Axum 0.8 route syntax ({param} instead of :param)
- Fix torznab search to use 'q' param instead of artist/album (Jackett only supports q)

Cargo.toml

@@ -23,6 +23,7 @@ thiserror = "2"
 url = "2"
 roxmltree = "0.20"
 base64 = "0.22"
+clap = { version = "4", features = ["derive"] }
 tonic = "0.12"
 prost = "0.13"