GigaMail 0.3.1

Small things noticed while recording the 0.3.0 demo.

• Grey text meets WCAG AA. Dates, captions, placeholders and every
  secondary label sat at 30-45% black on white (2.1-3.4:1, below the 4.5:1
  the AA level asks for). The floor is now 55% black (4.7:1), the
  --text-secondary token is 60%, and --text-muted — used but never
  defined — exists. A test scans the console sources so it cannot regress.
  Pointed out on r/UXDesign by u/Mrmasseno. Thank you.
• A calmer look, same identity. Card and list borders go from black at
  75% to a light grey; corners from 16/28px to 10/16px; shadows from heavy
  to barely there; six pixels of air between messages; the window buttons
  top-right match the pop-out button (flat tint, light border, soft
  shadow); the mail body sits in a rounded white card. The secondary
  windows lose a body shadow that had nowhere to go and smeared their
  bottom edge, and get thin scrollbars like the main window. Text never sits on a gradient any more: active chips, the
  selected message, title bars and the "New mail" button use a flat tint,
  and the pink-blue gradient stays only on the avatar, the logo and the
  microphone states. Every one of these came from r/UXDesign:
  u/AbilityRadiant2342 (the list) and u/el_paro (text over
  gradients). Two tests keep the dark borders and the gradients from
  creeping back.
• Dates and calendar follow the UI language. Every date, time, month and
  weekday name was formatted with the Italian locale regardless of the
  language chosen; the calendar window title and its "+ Event" button were
  Italian too. Formatting now uses the locale of the active language
  (it-IT, en-GB, zh-CN) and month/day names come from Intl.
• "From:" / "To:" in the mail detail were hardcoded in Italian.
• Dashboard no longer flashes "Loading…" on every folder change: the
  last rendered dashboard stays on screen while the data refreshes.
• Reply and new-mail windows are children of the main window, so they
  cannot end up behind a maximized main window (they had to be fished out
  of the taskbar).
• A 90-second demo video of the console lives in docs/demo/ and is
  linked from the README.
• npm test only runs tests/*.test.js (it used to pick up any .js
  under the console folder, including the embedded Python's own test files).