feat(realtime-api): WebRTC relay bridge

Cargo.toml

@@ -54,6 +54,7 @@ tokio-util = { version = "0.7", features = ["rt"] }
 tokio-tungstenite = { version = "0.29", features = ["rustls-tls-native-roots"] }
 webpki-roots = "1.0"
 multer = "3"
+str0m = { version = "0.16", default-features = false, features = ["openssl"] }
 scopeguard = "1.2"
 bitflags = "2.10.0"
 schemars = "0.8"

model_gateway/Cargo.toml

@@ -56,7 +56,7 @@ tracing-subscriber.workspace = true
 # Workspace dependencies (with extra features)
 axum = { workspace = true, features = ["macros", "ws", "tracing"] }
 bytemuck = { workspace = true, features = ["derive"] }
-reqwest = { workspace = true, features = ["stream", "blocking", "json", "rustls-tls"] }
+reqwest = { workspace = true, features = ["stream", "blocking", "json", "rustls-tls", "multipart"] }
 serde = { workspace = true, features = ["derive"] }
 tokio = { workspace = true, features = ["full"] }
 tokio-util.workspace = true
@@ -120,6 +120,8 @@ tokio-tungstenite = { workspace = true }
 webpki-roots = { workspace = true }
 wasmtime = { workspace = true }
 tempfile = "3.8"
+multer = { workspace = true }
+str0m = { workspace = true }
 
 [build-dependencies]
 chrono = { version = "0.4", features = ["clock"] }

model_gateway/src/routers/openai/realtime/mod.rs

@@ -2,12 +2,13 @@
 //!
 //! Supports three transport mechanisms:
 //! - **WebSocket** (server-to-server): Bidirectional WS proxy with transparent MCP interception
-//! - **WebRTC** (browser-to-server): SDP signaling proxy; media + data channel flow directly
+//! - **WebRTC** (browser-to-server): Dual peer-connection relay; SMG terminates both sides
 //! - **REST**: Ephemeral token generation (`client_secrets`, `sessions`, `transcription_sessions`)
 
 pub mod proxy;
 pub mod registry;
 pub mod rest;
+pub mod webrtc_bridge;
 pub mod ws;
 
 pub use registry::RealtimeRegistry;