feat: add operational reconnect and shutdown handling

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

src/signal.rs

@@ -0,0 +1,22 @@
+/// Cross-platform shutdown signal handling.
+///
+/// Provides a unified async future that resolves when the process should
+/// shut down (SIGINT/SIGTERM on Unix, Ctrl+C/Ctrl+Break on Windows).
+pub async fn shutdown_signal() {
+    #[cfg(unix)]
+    {
+        use tokio::signal::unix::{SignalKind, signal};
+        let mut sigint =
+            signal(SignalKind::interrupt()).expect("failed to create SIGINT signal handler");
+        let mut sigterm =
+            signal(SignalKind::terminate()).expect("failed to create SIGTERM signal handler");
+        tokio::select! {
+            _ = sigint.recv() => {},
+            _ = sigterm.recv() => {},
+        }
+    }
+    #[cfg(not(unix))]
+    {
+        tokio::signal::ctrl_c().await.ok();
+    }
+}