Classify legacy bridge JNI headers as private (#58811)

Summary:

Classifies `JavaModuleWrapper.h`, `JavaScriptExecutorHolder.h`, `JniJSModulesUnbundle.h`, `MethodInvoker.h` and `ModuleRegistryBuilder.h` from the `reactnativejni` target as "private" under the three-tier C++ stable API visibility model. They exist only to wire the legacy bridge and expose private `cxxreact` types. Consumers that opt into `RN_STRICT_API` now get an error if they include them directly; without that flag the guards are inert, so no existing build changes behaviour.

The remaining headers of `reactnativejni` are not classified yet.

Changelog: [Internal]

Differential Revision: D122764164

Author: j-piasecki

packages/react-native/ReactAndroid/src/main/jni/react/jni/CMakeLists.txt

@@ -80,6 +80,7 @@ target_link_libraries(reactnativejni
         glog_init
         logger
         react_cxxreact
+        react_cxxstableapi
         react_renderer_runtimescheduler
         reactnativejni_common
         runtimeexecutor

packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaModuleWrapper.h

@@ -7,6 +7,8 @@
 
 #pragma once
 
+#include <react/cxxstableapi/PrivateGuard.h>
+
 #include <cxxreact/NativeModule.h>
 #include <fbjni/fbjni.h>
 #include <optional>

packages/react-native/ReactAndroid/src/main/jni/react/jni/JavaScriptExecutorHolder.h

@@ -5,6 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+#include <react/cxxstableapi/PrivateGuard.h>
+
 #include <memory>
 
 #include <cxxreact/JSExecutor.h>

packages/react-native/ReactAndroid/src/main/jni/react/jni/JniJSModulesUnbundle.h

@@ -7,6 +7,8 @@
 
 #pragma once
 
+#include <react/cxxstableapi/PrivateGuard.h>
+
 #include <memory>
 
 #include <android/asset_manager.h>

packages/react-native/ReactAndroid/src/main/jni/react/jni/MethodInvoker.h

@@ -7,6 +7,8 @@
 
 #pragma once
 
+#include <react/cxxstableapi/PrivateGuard.h>
+
 #include <vector>
 
 #include <cxxreact/JSExecutor.h>

packages/react-native/ReactAndroid/src/main/jni/react/jni/ModuleRegistryBuilder.h

@@ -5,6 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+#include <react/cxxstableapi/PrivateGuard.h>
+
 #include <string>
 
 #include <cxxreact/CxxModule.h>