The `--option=value` handling splices the value into the argv to reuse the
`args[++i]` path, mutating the caller's array. The post-extension reparse in
runRootCommand then ran on that already-mutated argv, so
omp --model=sonnet --spawn-peer reviewer "review"
re-spliced `sonnet` and leaked it into the initial prompt before "review".
parseArgs now copies its input and never mutates the caller's array, so
launch, acp, and the reparse are all safe. Drops the now-redundant
`[...rawArgs]` copy at the reparse site, and adds regression coverage for the
--option=value + extension-flag combo plus input non-mutation.
