Standardise UX for checkboxes and toggle switches

Lichess is currently inconsistent in how it treats checkboxes () and toggle switches () for setting options.

Typical scenarios & best practice

1. Option saves or applies instantly (e.g. Notification settings, chat room display): display as toggle switch
2. Option requires further interaction (e.g. anywhere that requires users to first 'Submit' or 'Save', such as Advanced Search): display as a checkbox

Nielsen Norman Group hosts a page on best practices which provides more detail. As with everything in UX, there are exceptions. For example, Chess insights are in-keeping with best practices for search user interfaces, and needs no changes

Forms to review & remediate

The below list may not be exhaustive.

• "Evaluation bars" in studies and broadcasts Screenshot
• Study and broadcast sharing options Screenshot
• Arena tournament creation Screenshot
• Swiss tournament creation Screenshot
• Simul creation
• Broadcast creation Screenshot
  • Broadcast round creation/editing Screenshot
• Study creation
• Close account (https://lichess.org/account/close) Screenshot
• Delete account (https://lichess.org/account/delete) Screenshot
• API access tokens (https://lichess.org/account/oauth/token/create) Screenshot
• Lobby game filter - consider doing this as a separate PR to other changes, as it is heavily styled Screenshot
• Team creation, management Screenshot of new team creation - note there may be more
• Classes Screenshot of new class creation - I could not find any others
• Coach pages
  • Title verification Screenshot
• Streamer pages Screenshot
• Board editor (note this also appears in studies and is space-constrained; consider leaving for a separate PR to other changes) Screenshot
• Game import (https://lichess.org/paste) Screenshot
• Advanced search (https://lichess.org/games/search) Screenshot
• CMS (internal) Screenshot
• Blog post editor (must have saved a draft first) Screenshot
• Training (puzzles) - main screen
• Coordinate training
• Voice input
• Analysis menu
• Notifications
• In-game preferences (blindfold)
• Chess insights - making an exception here as the specific layout is common in search user interfaces, and Lichess's patterns are in keeping with it