Add FrankenPHP binary build workflow

[munezaclovis]

Summary

• Adds a GitHub Actions workflow to build static FrankenPHP binaries with multiple PHP versions (8.2, 8.3, 8.4, 8.5)
• FrankenPHP only ships one PHP version per binary; multi-version matrix is Docker-only upstream, so we build our own
• Binaries are built on macOS ARM64 (macos-14) using FrankenPHP's build-static.sh
• Creates GitHub Releases with named binaries (frankenphp-mac-arm64-phpX.Y) for pv install to download

How it works

1. resolve-version — fetches latest FrankenPHP release tag (or uses manual input)
2. build — matrix job: checks out dunglas/frankenphp, installs Go, runs build-static.sh with PHP_VERSION for each PHP version
3. release — collects all artifacts and creates/updates a GitHub release

Triggers

• workflow_dispatch — manual with optional frankenphp_ref input
• schedule — weekly (Monday midnight UTC)

Test plan

• Manually dispatch the workflow after merge
• Verify binaries build successfully for each PHP version
• Verify GitHub release is created with correct assets