Completion selection on Enter was gated to slash commands only
(value.startsWith('/')), so @file, ./path, and ~/path completions fell
through and submitted the incomplete input instead of inserting the
highlighted row.
Guard on completions.length && compReplace > 0 — useCompletion already
scopes population to slash and path tokens, and the next !== value check
keeps plain-text submits working when the completion is already applied.