feat(bindings)!: add RVM/Program support across FFI and language bindings (#565)

- FFI: add RVM/Program APIs, execution state accessors, HostAwait handling, and buffer/result helpers in rvm.rs, common.rs, engine.rs.
- Compiler: emit HostAwait for __builtin_host_await in function_calls.rs.
- RVM tests: add HostAwait regression cases and extend harness for suspend/resume responses in host_await.yaml and mod.rs.
- C/C++: add RVM tests/examples and wrapper updates in rvm_tests.c, rvm_tests.cpp, regorus.hpp, plus CMake wiring.
- C#: add Program/Rvm bindings, SafeHandle/PInvoke, tests, and example usage in Regorus, RvmProgramTests.cs, Program.cs, and README updates.
- Go: add Program/Rvm bindings, tests, and examples in rvm.go, rvm_test.go, main.go.
- Java: add Program/Rvm bindings, JNI glue, and examples in lib.rs, regorus, Test.java.
- Python: add Program/Rvm bindings and examples in lib.rs, test.py.
- WASM: add Program/Rvm bindings and examples in lib.rs, test.js.
- Tooling: wire binding tests in xtask and ignore generated Java artifacts in .gitignore.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

bindings/csharp/Regorus.Tests/RvmProgramTests.cs

@@ -0,0 +1,119 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Regorus.Tests;
+
+[TestClass]
+public sealed class RvmProgramTests
+{
+    private const string Policy = """
+package demo
+default allow = false
+allow if {
+  input.user == "alice"
+  some role in data.roles[input.user]
+  role == "admin"
+  count(input.actions) > 0
+}
+""";
+
+    private const string Data = """
+{
+  "roles": {
+    "alice": ["admin", "reader"]
+  }
+}
+""";
+
+    private const string Input = """
+{
+  "user": "alice",
+  "actions": ["read"]
+}
+""";
+
+    private const string HostAwaitPolicy = """
+package demo
+import rego.v1
+
+default allow := false
+
+allow if {
+  input.account.active == true
+  details := __builtin_host_await(input.account.id, "account")
+  details.tier == "gold"
+}
+""";
+
+    private const string HostAwaitInput = """
+{
+  "account": {
+    "id": "acct-1",
+    "active": true
+  }
+}
+""";
+
+    [TestMethod]
+    public void Program_compile_and_execute_succeeds()
+    {
+        var modules = new[] { new PolicyModule("demo.rego", Policy) };
+        var entryPoints = new[] { "data.demo.allow" };
+
+        var program = Program.CompileFromModules(Data, modules, entryPoints);
+        var listing = program.GenerateListing();
+        Assert.IsFalse(string.IsNullOrWhiteSpace(listing), "listing should be generated");
+
+        var binary = program.SerializeBinary();
+        var rehydrated = Program.DeserializeBinary(binary, out var isPartial);
+        Assert.IsFalse(isPartial, "program should be fully deserialized");
+
+        using var vm = new Rvm();
+        vm.LoadProgram(rehydrated);
+        vm.SetDataJson(Data);
+        vm.SetInputJson(Input);
+
+        var result = vm.Execute();
+        Assert.AreEqual("true", result, "expected allow=true");
+    }
+
+    [TestMethod]
+    public void Program_compile_from_engine_succeeds()
+    {
+        using var engine = new Engine();
+        engine.AddPolicy("demo.rego", Policy);
+
+        var program = Program.CompileFromEngine(engine, new[] { "data.demo.allow" });
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetDataJson(Data);
+        vm.SetInputJson(Input);
+
+        var result = vm.Execute();
+        Assert.AreEqual("true", result, "expected allow=true");
+    }
+
+      [TestMethod]
+      public void Program_host_await_suspend_and_resume_succeeds()
+      {
+        var modules = new[] { new PolicyModule("host_await.rego", HostAwaitPolicy) };
+        var entryPoints = new[] { "data.demo.allow" };
+
+        using var program = Program.CompileFromModules("{}", modules, entryPoints);
+        using var vm = new Rvm();
+        vm.SetExecutionMode(1);
+        vm.LoadProgram(program);
+        vm.SetInputJson(HostAwaitInput);
+
+        var initial = vm.Execute();
+        var state = vm.GetExecutionState();
+        Assert.IsNotNull(state, "execution state should be available");
+        StringAssert.Contains(state!, "HostAwait", "expected HostAwait suspension");
+
+        var resumed = vm.Resume("{\"tier\":\"gold\"}");
+        Assert.AreEqual("true", resumed, "expected allow=true after resume");
+      }
+}