* fix(tui): keep file suggestions open when typing in Tab-triggered mode
Previously, pressing Tab on an empty prompt or after a space would show
file suggestions, but typing a letter would dismiss them because the
text didn't look like a path pattern. Now the editor tracks whether
autocomplete was triggered via Tab (force mode) or naturally (regular
mode), and uses the appropriate suggestion method when updating.
* fix(tui): hide autocomplete when backspacing slash command to empty
Previously, typing / showed slash command suggestions, but pressing
Backspace to delete it showed file suggestions instead of hiding all
suggestions.