[precompile] added readme/doc files for precompile

packages/react-native/scripts/ios-prebuild/__docs__/README.md

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+# iOS Prebuild Scripts
+
+This directory contains scripts for prebuilding React Native itself into XCFrameworks for iOS and related platforms.
+
+## Overview
+
+These scripts automate the process of building React Native as a Swift Package and packaging it into XCFrameworks that can be distributed and consumed by iOS applications. The build process creates optimized frameworks for multiple architectures and platforms.
+
+## Purpose
+
+The prebuild scripts are used to:
+
+- Build React Native itself (not its dependencies) as XCFrameworks
+- Create distributable binaries for iOS, iOS Simulator, Catalyst, Vision, and visionOS platforms
+- Support both Debug and Release build configurations
+- Generate Debug Symbol (dSYM) files for debugging
+- Enable library evolution and module stability for Swift packages
+
+## Architecture
+
+The build system consists of several components:
+
+### `cli.js`
+The main entry point that orchestrates the build process. It:
+- Parses command-line arguments
+- Validates build parameters
+- Coordinates the build, archiving, and XCFramework creation steps
+
+### `build.js`
+Handles the Swift Package build process. It:
+- Executes `xcodebuild` commands with appropriate flags
+- Builds for specific platforms and build types (Debug/Release)
+- Locates and validates the generated framework artifacts
+- Uses build settings like `BUILD_LIBRARY_FOR_DISTRIBUTION=YES` for binary compatibility
+
+### `types.js`
+Defines TypeScript/Flow type definitions for:
+- `BuildFlavor`: Debug or Release configurations
+- `Destination`: Target platforms (iOS, iOS Simulator, Catalyst, Vision, visionOS)
+- `ArchiveOptions`: Configuration options for the build process
+
+### `utils.js`
+Provides utility functions including:
+- Logging functionality with prefixed output
+- Common helper functions used across scripts
+
+## Usage
+
+Run the prebuild script from the command line:
+
+```bash
+node cli.js [options]
+```
+
+### Options
+
+
+| Option | Alias | Type | Default | Description |
+|--------|-------|------|---------|-------------|
+| `--setup` | `-s` | boolean | - | Download and setup dependencies |
+| `--build` | `-b` | boolean | - | Build dependencies/platforms |
+| `--compose` | `-c` | boolean | - | Compose XCFramework from built dependencies |
+| `--platforms` | `-p` | array | `['ios', 'ios-simulator', 'mac-catalyst']` | Specify one or more platforms to build for |
+| `--flavor` | `-f` | string | `Debug` | Specify the flavor to build: `Debug` or `Release` |
+| `--identity` | `-i` | string | - | Specify the code signing identity to use for signing the frameworks |
+| `--help` | - | boolean | - | Show help information |
+
+
+### Build Process
+
+1. **Build Phase**: Compiles the React Native Swift Package for the specified platform and configuration
+2. **Archive Phase**: Collects the built frameworks from the derived data path
+3. **XCFramework Creation**: Packages the frameworks into XCFrameworks with debug symbols
+
+### Output Structure
+
+The build produces:
+- XCFrameworks in the specified output directory
+- Debug symbols (dSYM files) for debugging
+- Build products organized by platform and configuration
+
+## Build Flags
+
+The build process uses specific `xcodebuild` flags:
+
+- `BUILD_LIBRARY_FOR_DISTRIBUTION=YES`: Enables module stability
+- `SKIP_INSTALL=NO`: Ensures frameworks are properly installed
+- `DEBUG_INFORMATION_FORMAT="dwarf-with-dsym"`: Generates debug symbols
+- `OTHER_SWIFT_FLAGS="-no-verify-emitted-module-interface"`: Skips interface verification
+
+## Requirements
+
+- Xcode installed with command-line tools
+- Swift Package Manager support
+- macOS development environment
+- Node.js for running the scripts
+
+## Notes
+
+- These scripts build React Native itself, not third-party dependencies
+- The build process requires significant disk space for derived data
+- Build times vary depending on the target platform and configuration
+- XCFrameworks support multiple architectures in a single bundle
+
+## Known Issues
+
+The generated XCFrameworks currently use CocoaPods-style header structures rather than standard framework header conventions. This may cause modularity issues when:
+
+- Consuming the XCFrameworks in projects that expect standard framework headers
+- Building dependent frameworks that rely on proper module boundaries
+- Integrating with Swift Package Manager projects expecting modular headers
+
+## Usage
+
+To use the prebuilt React Native dependencies XCFrameworks in your iOS project, run pod install with the environment variable `RCT_USE_RN_DEP` set to `1`:
+
+```bash
+RCT_USE_RN_DEP=1 bundle exec pod install
+```
+
+For debugging and troubleshooting the Cocoapods scripts, you can use the following environment variables:
+
+- `RCT_USE_LOCAL_RN_DEP`: **TEST ONLY** If set, it will use a local tarball of ReactNativeDependencies if it exists.
+- `RCT_DEPS_VERSION`: **TEST ONLY** If set, it will override the version of ReactNativeDependencies to be used.

scripts/releases/ios-prebuild/__docs__/README.md

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+# iOS Prebuild Scripts Documentation
+
+This folder contains scripts for creating precompiled XCFrameworks for React Native's dependencies. These scripts automate the process of downloading, building, and packaging third-party libraries into distributable XCFramework bundles for iOS.
+
+## Overview
+
+The iOS prebuild system creates precompiled frameworks to reduce build times for React Native iOS apps. Instead of compiling dependencies from source during every build, these scripts package them as ready-to-use XCFrameworks.
+
+The prebuild process creates a Swift package that builds frameworks for the following 3rd party libraries:
+
+- boost
+- folly
+- glog
+- fmt
+- double-conversion
+- socketrocket
+- fast-float
+
+## Main Scripts
+
+### `cli.js`
+
+Command-line interface for the prebuild system. Provides the following options:
+
+```bash
+# Setup: Download and prepare dependencies
+node cli.js --setup
+
+# Build: Compile dependencies for specified platforms
+node cli.js --build --platforms ios,macos
+
+# Compose: Create XCFrameworks from built artifacts
+node cli.js --compose
+
+# Create Swift Package: Generate Package.swift file
+node cli.js --swiftpackage
+```
+
+**Options:**
+- `--setup` / `-s`: Download and setup dependencies
+- `--build` / `-b`: Build dependencies for target platforms
+- `--compose` / `-c`: Compose XCFrameworks from built artifacts
+- `--swiftpackage` / `-w`: Generate Package.swift file
+- `--platforms` / `-p`: Target platforms (ios, macos, catalyst, tvos, visionos)
+- `--configurations` / `-g`: Build configurations (Debug, Release)
+- `--dependencies` / `-d`: Specific dependencies to process
+- `--clean`: Clean build folder before building
+- `--identity` / `-i`: Signing identity for frameworks
+
+### `setupDependencies.js`
+
+Handles downloading and preparing third-party dependencies defined in `configuration.js`.
+
+**Functions:**
+- Downloads dependencies from specified URLs
+- Extracts archives (tar.gz, zip)
+- Runs preparation scripts for each dependency
+- Organizes source files in the build directory
+
+### `build.js`
+
+Compiles dependencies using Xcode for specified platforms and configurations.
+
+**Key features:**
+- Builds for multiple platforms: iOS, macOS, Catalyst, tvOS, visionOS
+- Supports both Debug and Release configurations
+- Creates universal binaries for device and simulator
+- Handles architecture-specific builds (arm64, x86_64)
+
+### `compose-framework.js`
+
+Creates the final XCFramework from built artifacts.
+
+**Functions:**
+
+#### `createFramework(scheme, configuration, dependencies, rootFolder, buildFolder, identity)`
+Composes XCFrameworks from platform-specific builds using `xcodebuild -create-xcframework`.
+
+#### `copyHeaders(scheme, dependencies, rootFolder)`
+Copies public headers from dependencies to the framework's Headers folder based on settings in `configuration.js`.
+
+#### `copyBundles(scheme, dependencies, outputFolder, frameworkPaths)`
+Copies resource bundles into the XCFramework's Resources folder.
+
+#### `copySymbols(scheme, outputFolder, frameworkPaths)`
+Copies debug symbols (dSYM files) to enable symbolication of crash reports.
+
+#### `signXCFramework(identity, xcframeworkPath)`
+Code signs the XCFramework with the specified identity.
+
+### `configuration.js`
+
+Defines all dependencies and their build settings.
+
+**Configuration structure:**
+```javascript
+{
+  name: 'boost',
+  version: '1.84.0',
+  url: new URL('https://...'),
+  files: {
+    sources: ['boost/**/*.hpp'],
+    headers: ['boost/**/*.hpp'],
+    resources: ['PrivacyInfo.xcprivacy']
+  },
+  settings: {
+    publicHeaderFiles: './',
+    headerSearchPaths: ['./'],
+    cCompilerFlags: ['-Wno-documentation'],
+    cxxCompilerFlags: ['-std=c++20']
+  }
+}
+```
+
+### `swift-package.js`
+
+Generates a Package.swift file for Swift Package Manager distribution.
+
+**Functions:**
+- `createSwiftPackageFile(dependencies, version, outputPath)`: Creates Package.swift with binary target definitions
+
+### `folders.js`
+
+Utility functions for folder operations.
+
+**Functions:**
+- `cleanFolder(folderPath)`: Removes and recreates a directory
+- `ensureFolder(folderPath)`: Creates directory if it doesn't exist
+
+### `constants.js`
+
+Defines shared constants used across scripts:
+- `HEADERS_FOLDER`: Location for extracted headers
+- `TARGET_FOLDER`: Build output location
+- `CPP_STANDARD`: C++ standard version to use
+
+### `types.js`
+
+Flow type definitions for TypeScript-style type checking:
+- `Platform`: Supported platform types
+- `Configuration`: Build configuration types
+- `Dependency`: Dependency configuration structure
+
+## Workflow
+
+The typical workflow for creating prebuilt frameworks:
+
+1. **Setup Phase** (`setupDependencies.js`)
+   - Downloads third-party dependencies
+   - Extracts archives
+   - Runs preparation scripts
+   - Organizes files in build directory
+
+2. **Build Phase** (`build.js`)
+   - Compiles each dependency for target platforms
+   - Creates fat binaries for device + simulator
+   - Generates build artifacts in platform-specific folders
+
+3. **Compose Phase** (`compose-framework.js`)
+   - Combines platform builds into XCFramework
+   - Copies headers and resources
+   - Includes debug symbols (dSYM)
+   - Code signs if identity provided
+
+4. **Package Phase** (`swift-package.js`)
+   - Generates Package.swift for SPM distribution
+   - Defines binary targets with checksums
+
+## Integration
+
+The prebuilt frameworks are consumed via CocoaPods or Swift Package Manager.
+
+Related files:
+- `packages/react-native/scripts/cocoapods/rndependencies.rb` - CocoaPods integration
+- `packages/react-native/React-Core-prebuilt.podspec` - Prebuilt React Core podspec
+
+## Entry Point
+
+The main entry point is `prepare-ios-prebuilds.js` which orchestrates the entire prebuild process:
+
+```javascript
+const {buildDepenencies} = require('./ios-prebuild/build');
+const {createFramework} = require('./ios-prebuild/compose-framework');
+const {setupDependencies} = require('./ios-prebuild/setupDependencies');
+```
+
+## Environment Variables
+
+- `RCT_USE_RN_DEP`: Use prebuilt dependencies instead of building from source
+- `RCT_USE_LOCAL_RN_DEP`: Use local tarball for testing
+- `RCT_SYMBOLICATE_PREBUILT_FRAMEWORKS`: Download and install dSYMs for symbolication
+
+See `packages/react-native/scripts/cocoapods/rncore.rb` for implementation details.
+
+## Usage
+
+To use the prebuilt React Native XCFrameworks in your iOS project, run pod install with the environment variable `RCT_USE_PREBUILT_RNCORE` set to `1`:
+
+```bash
+RCT_USE_PREBUILT_RNCORE=1 bundle exec pod install
+```
+
+This can be combined with `RCT_USE_RN_DEP=1` to use both React Native and its dependencies as prebuilt frameworks.
+
+For debugging and troubleshooting the Cocoapods scripts, you can use the following environment variables:
+
+- `RCT_TESTONLY_RNCORE_TARBALL_PATH`: **TEST ONLY** If set, it will use a local tarball of RNCore if it exists.
+- `RCT_TESTONLY_RNCORE_VERSION`: **TEST ONLY** If set, it will override the version of RNCore to be used.
+- `RCT_SYMBOLICATE_PREBUILT_FRAMEWORKS`: If set to 1, it will download the dSYMs for the prebuilt RNCore frameworks and install these in the framework folders