v0.3.10-alpha

v0.3.10-alpha — unify picker UX (arrow-key /key + confirm single-char)

Fix 4 UX bugs user reported in v0.3.9:
- /key menu: arrow-key navigation (was: readline digit input)
- Tool confirm: single keystroke y/n works (was: 'yy' from echo race → deny)
- /key: auto-close after successful key store
- Masked paste line cleared on exit (was: 100+ star leak)

All fixes funnel through unified pickOne widget. Consistent with nimbus init.
Fixes raw-mode echo race in makeOnAsk.

1957 tests green (+21 regression tests).