- EZ: picking a punctuation/symbol from a key's long-press popup
  now keeps it in the pre-edit buffer instead of committing it
  straight to the editor.
- Switching between keyboard layouts now commits the already-
  selected pre-edit characters first (incomplete EZ roots are
  dropped since they're meaningless in the next layout).
- English: keycaps show the shifted alternate (e.g. ! above 1,
  : above ;) at the top-left of each symbol key.
- IME now auto-picks the most useful layout for the target field:
  numeric/phone/date fields → Numbers; email/URI/password fields
  → English.
- Password fields, fields with TYPE_TEXT_FLAG_NO_SUGGESTIONS, and
  fields with IME_FLAG_NO_PERSONALIZED_LEARNING now run English in
  "asciiOnly" mode — no prediction bar, no composing buffer, no
  learned frequencies — so typed prefixes never surface on screen
  or feed the prediction trie.
- Fix: inserting a punctuation while in candidate-selection mode
  no longer leaves the selection flag stuck; the next digit press
  commits a digit instead of selecting a stale candidate.
