chore: include macOS slice in universal hermes xcframework

Consolidates the three separate Hermes Apple build scripts into a single
`build-apple-framework.sh` that builds all platforms — including macOS —
into one universal `hermesvm.xcframework`.

Previously macOS was built as a standalone `.framework` by a separate script
and excluded from the universal xcframework. This meant macOS had a different
distribution path from every other Apple platform.

- Merge `build-ios-framework.sh` and `build-mac-framework.sh` into
  `build-apple-framework.sh` using the `PLATFORMS` array as single source
  of truth
- Update podspec to point macOS at the universal xcframework
- Update CI workflows to use `build-apple-framework.sh` uniformly for
  all slices (no more macOS special-casing)
- Remove standalone macOS framework validation from hermes-utils.js

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Saadnajmi

.github/workflows/build-hermes-macos.yml

@@ -60,7 +60,7 @@ jobs:
       - name: Create universal xcframework
         shell: bash
         run: |
-          echo "[HERMES] Creating the universal framework (including macOS)"
+          echo "[HERMES] Creating the universal framework"
           chmod +x ./utils/build-apple-framework.sh
           ./utils/build-apple-framework.sh build_framework