On SELinux-enforcing systems (Fedora, RHEL, CentOS), binaries installed to
non-standard locations need proper security contexts for systemd to execute
them. Without this, systemd fails with 'Permission denied' even when the
binary has correct Unix permissions.
Changes:
- Add restore_selinux_contexts() function to both install scripts
- Uses restorecon (preferred) or chcon (fallback) to set bin_t context
- Only runs when SELinux is detected and enforcing
- Called after binary installation, before systemd service start