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/Engine.cs

@@ -441,7 +441,7 @@ namespace Regorus
             }
         }
 
-        private RegorusEngineHandle GetHandleForUse()
+        internal RegorusEngineHandle GetHandleForUse()
         {
             var handle = _handle;
             if (handle is null || handle.IsClosed || handle.IsInvalid)
@@ -451,7 +451,7 @@ namespace Regorus
             return handle;
         }
 
-        private void UseHandle(Action<IntPtr> action)
+        internal void UseHandle(Action<IntPtr> action)
         {
             UseHandle<object?>(handlePtr =>
             {
@@ -460,7 +460,7 @@ namespace Regorus
             });
         }
 
-        private T UseHandle<T>(Func<IntPtr, T> func)
+        internal T UseHandle<T>(Func<IntPtr, T> func)
         {
             var handle = GetHandleForUse();
             bool addedRef = false;
@@ -484,5 +484,10 @@ namespace Regorus
             }
         }
 
+        internal T UseHandleForInterop<T>(Func<IntPtr, T> func)
+        {
+            return UseHandle(func);
+        }
+
     }
 }