fix(archsetup): log the real exit code from failed installs

`retry_install` was logging "error code: 0" for every retry-exhausted install (6 AUR packages on the 2026-05-16 run, 2 on the 2026-05-18 run). Root cause: `last_exit_code=$?` ran AFTER an `if eval ...; then return 0; fi` block. Bash defines an if-compound's exit status as zero when no condition tested true. With no else clause and a failing eval, that's exactly what happens, so `$?` captures 0 instead of eval's actual exit code.

Now eval runs unconditionally, `$?` lands in `last_exit_code` right after it, and the if just compares against the captured value. Same control flow, accurate codes in the summary. Verified with a small bash test: the old pattern reports `$?=0` after a failing if, the new pattern reports the real exit.

0 files changed, 0 insertions, 0 deletions