cd87b82ac0
Without an after-separator state, the new unknown-flag guard rejected flag-shaped prompts (`omp -p -- --explain-this`): the loop dropped the `--` token and then re-validated `--explain-this`, recorded it in `unrecognizedFlags`, and exited 2. parseArgs now flips a `sawSeparator` latch on `--` and short-circuits the remaining tokens straight into `messages` — no built-in dispatch, no extension match, no `@file` expansion. Two regression tests cover the flag-shaped and `@`-prefixed cases. Refs #2459