- Write nested sub-extension ZIPs to subdirectory to prevent filename
collisions with outer package ZIPs (deferred ZipArchive::addFile reads)
- Apply exclude patterns to nested top-level files (parity with outer)
- Patch nested manifest with folder="packages" so Joomla finds sub-ZIPs
- Include all top-level directories (not just language/) in nested packages
Claude-Session: https://claude.ai/code/session_01MbEjBtsSjPuTWhqqrMS2wG
When a sub-package directory contains its own pkg_*.xml manifest and
packages/ directory (e.g. a git submodule), recursively build each
sub-extension into ZIPs before assembling the outer package ZIP.