Fixes#12175
If a user types an npm package name with multiple `@` symbols like `npx
-y @foo/bar@latest`, the TUI currently treats this as though it's
attempting to invoke the file picker.
### What changed
- **Generalized `@` token parsing**
- `current_prefixed_token(...)` now treats `@` as a token start **only
at a whitespace boundary** (or start-of-line).
- If the cursor is on a nested `@` inside an existing
whitespace-delimited token (for example `@scope/pkg@latest`), it keeps
the surrounding token active instead of starting a new token at the
second `@`.
- It also avoids misclassifying mid-word usages like `foo@bar` as an `@`
file token.
- **Enter behavior with file popup**
- If the file-search popup is open but has **no selected match**,
pressing `Enter` now closes the popup and falls through to normal submit
behavior.
- This prevents pasted strings containing `@...` from blocking
submission just because file-search was active with no actionable
selection.
### Testing
I manually built and tested the scenarios involved with the bug report
and related use of `@` mentions to verify no regressions
Eric Traut
74cebceed7