feat(rust): add rust sdk (#5909)

* upload client

* add gh workflow

* refactor build script

* remove dbg!

* fix async

* remove unused

* update dev.nu

* update CI

* fix ci

* fixin tests

* fixes + tests

rust-client/src/maybe_future.rs

@@ -0,0 +1,48 @@
+// #[cfg(feature = "async")]
+// use futures::future::BoxFuture;
+
+/// A conditional type that represents either:
+/// - A boxed future (async mode)
+/// - A direct value (sync mode)
+pub mod maybe_future {
+    #[cfg(feature = "async")]
+    pub type MaybeFuture<'a, T> = futures::future::BoxFuture<'a, T>;
+    #[cfg(not(feature = "async"))]
+    pub type MaybeFuture<'a, T> = T;
+}
+
+/// Bridges between async and sync execution contexts
+///
+/// Behavior depends on compilation:
+/// - With `async` feature: Returns a boxed future
+/// - Without `async` feature: Blocks on the global runtime
+#[macro_export]
+macro_rules! ret {
+    ($ex:expr) => {
+        #[cfg(feature = "async")]
+        return async move { $ex.await }.boxed();
+
+        #[cfg(not(feature = "async"))]
+        return crate::maybe_future::RUNTIME.block_on($ex);
+    };
+}
+
+/// The global Tokio runtime instance used in sync mode
+///
+/// Initialized lazily with:
+/// - I/O capabilities
+/// - Time utilities
+/// - Current-thread executor
+///
+/// # Panics
+///
+/// If Tokio fails to initialize the runtime
+#[cfg(not(feature = "async"))]
+pub(crate) static RUNTIME: once_cell::sync::Lazy<tokio::runtime::Runtime> =
+    once_cell::sync::Lazy::new(|| {
+        tokio::runtime::Builder::new_current_thread()
+            .enable_io()
+            .enable_time()
+            .build()
+            .unwrap()
+    });