Add API to get version information (#2309)

flutter/sherpa_onnx/lib/src/version.dart

@@ -0,0 +1,31 @@
+// Copyright (c)  2025  Xiaomi Corporation
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import './sherpa_onnx_bindings.dart';
+
+String getVersion() {
+  Pointer<Utf8> version = SherpaOnnxBindings.getVersionStr?.call() ?? nullptr;
+  if (version == nullptr) {
+    return '';
+  }
+
+  return version.toDartString();
+}
+
+String getGitSha1() {
+  Pointer<Utf8> gitSha1 = SherpaOnnxBindings.getGitSha1?.call() ?? nullptr;
+  if (gitSha1 == nullptr) {
+    return '';
+  }
+
+  return gitSha1.toDartString();
+}
+
+String getGitDate() {
+  Pointer<Utf8> gitDate = SherpaOnnxBindings.getGitDate?.call() ?? nullptr;
+  if (gitDate == nullptr) {
+    return '';
+  }
+
+  return gitDate.toDartString();
+}