feat(rust-proxy-engine): add a Rust SIP proxy engine with shared SIP and codec libraries

rust/crates/proxy-engine/src/ipc.rs

@@ -0,0 +1,47 @@
+//! IPC protocol — command dispatch and event emission.
+//!
+//! All communication with the TypeScript control plane goes through
+//! JSON-line messages on stdin/stdout (smartrust protocol).
+
+use serde::Deserialize;
+use tokio::sync::mpsc;
+
+/// Sender for serialized stdout output.
+pub type OutTx = mpsc::UnboundedSender<String>;
+
+/// A command received from the TypeScript control plane.
+#[derive(Deserialize)]
+pub struct Command {
+    pub id: String,
+    pub method: String,
+    #[serde(default)]
+    pub params: serde_json::Value,
+}
+
+/// Send a response to a command.
+pub fn respond(tx: &OutTx, id: &str, success: bool, result: Option<serde_json::Value>, error: Option<&str>) {
+    let mut resp = serde_json::json!({ "id": id, "success": success });
+    if let Some(r) = result {
+        resp["result"] = r;
+    }
+    if let Some(e) = error {
+        resp["error"] = serde_json::Value::String(e.to_string());
+    }
+    let _ = tx.send(resp.to_string());
+}
+
+/// Send a success response.
+pub fn respond_ok(tx: &OutTx, id: &str, result: serde_json::Value) {
+    respond(tx, id, true, Some(result), None);
+}
+
+/// Send an error response.
+pub fn respond_err(tx: &OutTx, id: &str, error: &str) {
+    respond(tx, id, false, None, Some(error));
+}
+
+/// Emit an event to the TypeScript control plane.
+pub fn emit_event(tx: &OutTx, event: &str, data: serde_json::Value) {
+    let msg = serde_json::json!({ "event": event, "data": data });
+    let _ = tx.send(msg.to_string());
+}