[RNE Rewrite] refactor: provision headers via download, not git

Drop the committed third-party/include header set (~200K LOC of vendored
ExecuTorch/c10/torch/opencv headers). Headers are now downloaded like the
binaries: a platform-independent headers.tar.gz fetched by download-libs.js
and produced by package-release-artifacts.sh. Keeps the rewrite's 'no
third-party in git' philosophy and avoids churn on ExecuTorch bumps.

Author: msluszniak

packages/react-native-executorch/package.json

@@ -22,8 +22,8 @@
     "cpp",
     "scripts",
     "*.podspec",
-    "third-party/include",
     "third-party",
+    "!third-party/include",
     "!third-party/android/jniLibs",
     "!third-party/android/libs",
     "!third-party/ios/Frameworks",

packages/react-native-executorch/scripts/download-libs.js

@@ -7,6 +7,8 @@
  *
  * Artifact layout on GitHub Releases (per version tag, e.g. v0.9.0):
  *
+ *   headers.tar.gz                   -- ExecuTorch + c10 + torch + tokenizers + opencv
+ *                                       headers (platform-independent; always downloaded)
  *   core-android-arm64-v8a.tar.gz    -- executorch, pthreadpool, cpuinfo for arm64
  *   core-android-x86_64.tar.gz       -- executorch for x86_64
  *   core-ios.tar.gz                  -- ExecutorchLib.xcframework (without xnnpack/coreml)
@@ -269,6 +271,11 @@ function detectTargets() {
 function getArtifacts(targets, { backends, libs }) {
   const artifacts = [];
 
+  // Headers (ExecuTorch + c10 + torch + tokenizers + opencv) are
+  // platform-independent and always needed at build time. The tarball contains
+  // an `include/` dir, so it extracts to third-party/include/.
+  artifacts.push(makeArtifact('headers', THIRD_PARTY_DIR));
+
   for (const target of targets) {
     const destDir = target.startsWith('android')
       ? path.join(THIRD_PARTY_DIR, 'android', 'libs')

packages/react-native-executorch/scripts/package-release-artifacts.sh

@@ -54,6 +54,7 @@ ANDROID_LIBS="$PACKAGE_ROOT/third-party/android/libs"
 IOS_DIR="$PACKAGE_ROOT/third-party/ios"
 OUT="$PACKAGE_ROOT/dist-artifacts"
 
+INCLUDE_DIR="$PACKAGE_ROOT/third-party/include"
 VERSION=$(node -p "require('$PACKAGE_ROOT/package.json').version")
 
 echo "Packaging release artifacts for v$VERSION"
@@ -137,6 +138,16 @@ package_merged() {
   rm -rf "$tmp"
 }
 
+# ---- Headers ----------------------------------------------------------------
+# Platform-independent ExecuTorch + c10 + torch + tokenizers + opencv headers.
+# Staged under include/ so the tarball extracts to third-party/include/.
+
+echo ""
+echo "Headers:"
+
+package_merged "headers" \
+  "include"   "$INCLUDE_DIR"
+
 # ---- Android ----------------------------------------------------------------
 
 echo ""

packages/react-native-executorch/third-party/.gitignore

@@ -4,9 +4,11 @@
 # Committed here (source, not per-build binaries):
 #   - README.md, this .gitignore
 #   - common/            (phonemis submodule, built from source)
-#   - include/           (ExecuTorch + c10 + tokenizer headers — matches main)
 #   - ios/ExecutorchLib/ (xcodeproj wrapper that builds ExecutorchLib.xcframework)
 
+# --- Headers (ExecuTorch + c10 + tokenizer + opencv) — downloaded, not committed ---
+/include/
+
 # --- Android: downloaded per-ABI binaries ---
 /android/jniLibs/
 /android/libs/executorch/

packages/react-native-executorch/third-party/README.md

@@ -5,10 +5,6 @@ Native ExecuTorch artifacts are split into **committed source** and
 
 ## Committed to git
 
-- `include/` — ExecuTorch + c10 + torch headers, including the `pytorch/tokenizers`
-  headers under `include/executorch/extension/llm/tokenizers/include` (used by the
-  nlp/tokenizer extension; the `tokenizers::HFTokenizer` symbols resolve from
-  `libexecutorch`, which is built with the llm/tokenizers extension).
 - `ios/ExecutorchLib/` — the Xcode project that wraps the prebuilt ExecuTorch
   static archives into `ExecutorchLib.xcframework` (used only when (re)building
   the iOS release artifacts).
@@ -25,6 +21,8 @@ read to gate `RNE_ENABLE_*` and link only the requested backends.
 
 Extracted layout the podspec / `android/CMakeLists.txt` expect:
 
+- `include/` — ExecuTorch + c10 + torch + `pytorch/tokenizers` + opencv headers
+  (from `headers.tar.gz`, always downloaded; platform-independent)
 - `android/libs/executorch/<abi>/libexecutorch.so` (+ `libxnnpack_executorch_backend.so`,
   `libvulkan_executorch_backend.so` when those backends are enabled)
 - `android/libs/opencv/<abi>/*.a`, `android/libs/opencv-third-party/<abi>/libkleidicv*.a`