fix(iOS): stamp the React Native version in the prebuild compose job (#57603)

Summary:
`prebuild-ios-core.yml` builds the prebuilt iOS core in two jobs: **`build-rn-slice`** compiles the React binary per platform slice, and **`compose-xcframework`** runs afterwards in its **own fresh checkout**, downloads the slice artifacts, and composes the shipped `React.xcframework` + `ReactNativeHeaders.xcframework` — re-deriving the shipped *headers* from that checkout.

The "Set React Native version" step runs only in `build-rn-slice`. So the compiled **binary is stamped**, but the composed **headers are not**: the artifact ships `ReactNativeVersion.h` with the `1000.0.0` dev sentinel, internally inconsistent with its own binary (and with the npm package, which is stamped in its own publish job).

This was latent for as long as the compose job has existed — it only started breaking consumers now because the header-facades / VFS-overlay-removal work changed *which file libraries actually read*. Previously header resolution (the VFS overlay, and the `Pods/Headers/Public` symlinks of the source pods) redirected reads to the **stamped npm copy**, so the sentinel bytes in the tarball were never consumed. With real materialized headers, the prebuilt copy now wins the search path, and any library gating on `REACT_NATIVE_VERSION_MAJOR/MINOR` compiles the wrong branch. That breaks `[ios] react-native-unistyles` in nightly-tests: its `#if REACT_NATIVE_VERSION_MINOR >= 81` sees `MINOR 0` and picks a removed pre-0.81 path (`shadowNodeFromValue`).

**Fix — built-headers overlay (no re-stamp/revert).** The `build-rn-slice` job already stamps its checkout before building and uploads `.build/headers`, and the compose job already downloads it — it was just unused. `stageEntries` now takes an overlay dir and, **for `ReactNativeVersion.h` only**, prefers the built copy (stamped in the slice job) over the source sentinel. Header **layout** is still spec-derived from source (podspec inventory, collision detection, classification), and every **other** header still copies from source — so a stale build tree can never ship wrong header content, only the one build-generated version header is overlaid. No stamping of the compose checkout, no `git revert`, no cache-key desync.

The compose cache key is bumped so pre-fix (unstamped) composed artifacts cached under the old key are not served.

**Guard.** `headers-verify.js` gains `--require-stamped-version` (passed when a `version-type` is set) that hard-fails the compose verification if any composed `ReactNativeVersion.h` still contains the sentinel — turning any future regression into a red prebuild instead of silently broken community libraries.

## Changelog:

[IOS] [FIXED] - Ship a version-stamped ReactNativeVersion.h in the prebuilt iOS core artifacts instead of the 1000.0.0 dev sentinel

Pull Request resolved: https://github.com/react/react-native/pull/57603

Test Plan:
- Local compose with a stamped `ReactNativeVersion.h` seeded into `.build/headers` and the source tree left at the `1000` sentinel: all composed `ReactNativeVersion.h` copies come out stamped (overlay won), while a deliberately **stale** `.build/headers/…/TraceRecordingState.h` is correctly ignored — the composed `TraceRecordingState.h`/`HostTracingProfile.h` come from source, and other headers + module maps/umbrellas are unaffected (structural gate passes).
- Guard: composed layout with a sentinel header → `verifyVersionStamp` throws listing the offending files; stamped → `version stamp OK (N copies checked)`; no effect without the flag.
- Verified against a fresh RN-nightly app + `react-native-unistyles@3.3.0` on Xcode 26.3 (prebuilt mode) and in the Expo prebuilt harness (26.3 + 26.6): stock prebuilt headers reproduce the `shadowNodeFromValue` error; the stamped prebuilt header resolves it.
- End-to-end proof is the next nightly run: the composed tarball must carry a stamped header.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed By: javache

Differential Revision: D113005220

Pulled By: cipolleschi

fbshipit-source-id: 5fbba8bb4e84fd1458a2f4a0baa623cf613b6e3b

.github/workflows/prebuild-ios-core.yml

@@ -133,7 +133,7 @@ jobs:
         uses: actions/cache/restore@v5
         with:
           path: packages/react-native/.build/output/xcframeworks
-          key: v3-ios-core-xcframework-${{ matrix.flavor }}-${{ hashFiles('packages/react-native/Package.swift', 'packages/react-native/scripts/ios-prebuild/*.js', 'packages/react-native/scripts/ios-prebuild.js', 'packages/react-native/React/**/*', 'packages/react-native/ReactCommon/**/*', 'packages/react-native/Libraries/**/*') }}
+          key: v4-ios-core-xcframework-${{ matrix.flavor }}-${{ hashFiles('packages/react-native/Package.swift', 'packages/react-native/scripts/ios-prebuild/*.js', 'packages/react-native/scripts/ios-prebuild.js', 'packages/react-native/React/**/*', 'packages/react-native/ReactCommon/**/*', 'packages/react-native/Libraries/**/*') }}
       - name: Setup node.js
         if: steps.restore-ios-xcframework.outputs.cache-hit != 'true'
         uses: ./.github/actions/setup-node
@@ -200,7 +200,7 @@ jobs:
           # privileged-consumer/Expo fixtures). Catches consumer-facing header
           # regressions here instead of in downstream builds.
           cd packages/react-native
-          node scripts/ios-prebuild/headers-verify.js --flavor "${{ matrix.flavor }}"
+          node scripts/ios-prebuild/headers-verify.js --flavor "${{ matrix.flavor }}" ${{ inputs.version-type != '' && '--require-stamped-version' || '' }}
       - name: Compress and Rename XCFramework
         if: steps.restore-ios-xcframework.outputs.cache-hit != 'true'
         run: |
@@ -246,4 +246,4 @@ jobs:
             packages/react-native/.build/output/xcframeworks/ReactCore${{matrix.flavor}}.xcframework.tar.gz
             packages/react-native/.build/output/xcframeworks/ReactCore${{matrix.flavor}}.framework.dSYM.tar.gz
             packages/react-native/.build/output/xcframeworks/ReactNativeHeaders${{matrix.flavor}}.xcframework.tar.gz
-          key: v3-ios-core-xcframework-${{ matrix.flavor }}-${{ hashFiles('packages/react-native/Package.swift', 'packages/react-native/scripts/ios-prebuild/*.js', 'packages/react-native/scripts/ios-prebuild.js', 'packages/react-native/React/**/*', 'packages/react-native/ReactCommon/**/*', 'packages/react-native/Libraries/**/*') }}
+          key: v4-ios-core-xcframework-${{ matrix.flavor }}-${{ hashFiles('packages/react-native/Package.swift', 'packages/react-native/scripts/ios-prebuild/*.js', 'packages/react-native/scripts/ios-prebuild.js', 'packages/react-native/React/**/*', 'packages/react-native/ReactCommon/**/*', 'packages/react-native/Libraries/**/*') }}