Add optional React Compiler support as build feature

Add React Compiler as an optional optimization feature that can be enabled
via USE_REACT_COMPILER CMake option. When enabled, Babel preprocesses React
components to add automatic memoization before bundling with esbuild.

Changes:
- Add babel-plugin-react-compiler and glob to package.json devDependencies
- Create .babelrc.cjs with conditional React Compiler plugin
- Implement two-pass build in bundle-react-unit.js (Babel → esbuild)
- Add USE_REACT_COMPILER CMake option (OFF by default)
- Pass environment variable from CMake to build script
- Add .babelrc.cjs to build dependencies for proper rebuild tracking

The feature is zero-cost when disabled - no Babel overhead, identical
esbuild configuration, and no behavior changes. When enabled, components
are automatically optimized with memoization to reduce re-renders.

Author: tmikov

.babelrc

@@ -0,0 +1,10 @@
+module.exports = {
+  presets: [
+    ['@babel/preset-react', { runtime: 'automatic' }]
+  ],
+  plugins: [
+    process.env.USE_REACT_COMPILER === 'true'
+      ? 'babel-plugin-react-compiler'
+      : null
+  ].filter(Boolean)
+};

.babelrc.cjs

@@ -31,10 +31,14 @@ if(NOT DEFINED REACT_BUNDLE_MODE)
 endif()
 set(REACT_BUNDLE_MODE ${REACT_BUNDLE_MODE} CACHE STRING "React bundle compilation mode (0=native, 1=bytecode, 2=source)")
 
+# React Compiler: Optional optimization feature (OFF by default)
+option(USE_REACT_COMPILER "Enable React Compiler for automatic memoization optimizations" OFF)
+
 message(STATUS "Hermes build: ${HERMES_BUILD}")
 message(STATUS "Hermes source: ${HERMES_SRC}")
 message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
 message(STATUS "React bundle mode: ${REACT_BUNDLE_MODE} (0=native, 1=bytecode, 2=source)")
+message(STATUS "React Compiler: ${USE_REACT_COMPILER}")
 
 # Collect reconciler library files for dependency tracking
 # This is defined at root level so it can be reused by multiple apps

CMakeLists.txt

@@ -62,6 +62,7 @@ _**Note**: This project is an independent experiment and is not affiliated with,
   - Lightning-fast startup - no parsing, no JIT warmup, just native code execution
   - Single executable distribution
 - ✅ **React 19.2.0** with custom reconciler
+- ✅ **React Compiler support** - Optional automatic memoization optimization
 - ✅ **Static Hermes** with zero-overhead FFI to Dear ImGui
 - ✅ **Event loop** with `setTimeout`, `setImmediate`, and Promise support
 - ✅ **React hooks** (`useState`, `useEffect`, etc.)
@@ -994,6 +995,21 @@ Override the mode explicitly:
 cmake -B cmake-build-debug -DCMAKE_BUILD_TYPE=Debug -DREACT_BUNDLE_MODE=1
 ```
 
+### React Compiler (Optional)
+
+React Compiler is an optional build feature that automatically adds memoization to React components. It's disabled by default and can be enabled via CMake:
+
+```bash
+cmake -B build -DUSE_REACT_COMPILER=ON
+cmake --build build
+```
+
+**How it works:**
+- Uses a two-pass build: Babel preprocessing → esbuild bundling
+- Babel transforms React components to add `useMemoCache` calls
+- Components skip re-renders when props/state haven't changed
+- Works with all compilation modes (native/bytecode/source)
+
 ### Hermes Build Integration
 
 Hermes is **automatically** cloned and built as part of the CMake configuration—no manual setup required:

README.md

@@ -80,20 +80,23 @@ function(add_react_imgui_app)
         ${RECONCILER_FILES}
         ${APP_FILES}
         ${CMAKE_SOURCE_DIR}/scripts/bundle-react-unit.js
+        ${CMAKE_SOURCE_DIR}/.babelrc.cjs
     )
     if(ARG_ADDITIONAL_JS_DEPS)
         list(APPEND REACT_UNIT_DEPS ${ARG_ADDITIONAL_JS_DEPS})
     endif()
 
     # Bundle with esbuild
     add_custom_command(OUTPUT ${REACT_UNIT_BUNDLE}
-        COMMAND node ${CMAKE_SOURCE_DIR}/scripts/bundle-react-unit.js
+        COMMAND ${CMAKE_COMMAND} -E env
+            USE_REACT_COMPILER=$<IF:$<BOOL:${USE_REACT_COMPILER}>,true,false>
+            node ${CMAKE_SOURCE_DIR}/scripts/bundle-react-unit.js
             ${ARG_ENTRY_POINT}
             ${REACT_UNIT_BUNDLE}
             $<IF:$<CONFIG:Debug>,development,production>
         DEPENDS ${REACT_UNIT_DEPS}
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-        COMMENT "Bundling ${ARG_TARGET} React unit with esbuild (NODE_ENV=$<IF:$<CONFIG:Debug>,development,production>)"
+        COMMENT "Bundling ${ARG_TARGET} React unit with esbuild (NODE_ENV=$<IF:$<CONFIG:Debug>,development,production>, React Compiler=${USE_REACT_COMPILER})"
     )
 
     # Compile based on REACT_BUNDLE_MODE