Unify main() error-path cleanup

[henrybear327]

Summary by cubic

Centralized main() cleanup with a goto-based unwind to ensure consistent resource release on all exits and fix a temporary ELF file leak. This reduces duplicated error-path code and makes failure handling more reliable.

• Bug Fixes

  • Always unlink the temporary host ELF (elf_host_path) on any exit, covering post-prepare failures and Rosetta teardown.
  • Route the success path through cleanup to ensure sysroot unmount, cwd restore, and argv/path frees always run.

• Refactors

  • Replaced repeated cleanup-and-return blocks with fail/cleanup labels and a single exit_code.
  • Removed duplicated per-branch cleanup and unlink calls, simplifying control flow.

^{Written for commit ae65cf1. Summary will update on new commits.}

[jserv]

Thank @henrybear327 for contributing!