🐛 fix: install XcodeGen bundled resources

[gaelfoppolo]

Summary

This fixes a regression where the plugin installs only the xcodegen executable but omits XcodeGen’s bundled runtime resources (e.g. share/xcodegen and/or XcodeGen_XcodeGenKit.bundle).

When those resources are missing, xcodegen generate prints messages like:

• No "base" settings found
• No "release config" settings found
• No "debug config" settings found
• No "iOS" settings found

…and the generated .xcodeproj can end up with incomplete/empty build settings (e.g. SWIFT_VERSION missing) which then breaks downstream xcodebuild runs.

Root cause

The current install_version() implementation copies only:

• ${ASDF_DOWNLOAD_PATH}/bin/xcodegen

But XcodeGen releases are not “single binary only”; they ship additional resources required at runtime.

Fix

• Install the full extracted archive payload into the asdf install prefix (ASDF_INSTALL_PATH), not just bin/xcodegen.
• Add a sanity check to fail fast if the bundled resources are missing after install (expects either share/xcodegen or XcodeGen_XcodeGenKit.bundle).

How to validate

asdf plugin add xcodegen https://github.com/younke/asdf-xcodegen.git
asdf install xcodegen 2.43.0

XCODEGEN_BIN="$(asdf which xcodegen)"
echo "$XCODEGEN_BIN"
ls -la "$(dirname "$XCODEGEN_BIN")/../share/xcodegen" || true

xcodegen generate

Expected:

- resource directory (or bundle) exists alongside the installed binary
- xcodegen generate runs without the “No … settings found” warnings

[younke]

@gaelfoppolo lgtm, ty