Fixes an interactive-picker bug that made datumctl login unusable on Windows.
What's new
- Windows picker input fix — arrow keys now work in the context picker shown after
datumctl loginon Windows. A background reader watching for^Dcouldn't be interrupted on Windows console handles, so it kept holding the terminal in line-input mode and ate the picker's keystrokes. The watcher now detects when it can't be interrupted and skips watching, so login on Windows cancels via^Conly. Unix behavior is unchanged. (#267)