Peritext rendering surface UI improvements

[streamich]

• [x] Ability to provide custom renderers for all elements.
  • [x] Caret
  • [x] Selection anchor
  • [x] Selection focus
  • [x] Selection body
  • [x] Inline
  • [x] Leaf block
  • [x] Block
  • [x] Whole document
• [x] Ability to compose many renderer maps together.
• [ ] Ability to add custom events.
• [x] Handle soft line navigation.
  • [x] Detect soft line wrap boundaries.
• [ ] Ability to provide suggestions, inlay hints.
  • [ ] Spellcheking
  • [ ] Integration with LLM
• [ ] Add concept of blurred cursor. The cursor becomes grey when editor loses focus, when editor regains focus, the starting cursor position is where the blurred cursor was left.
• [ ] When navigating with ArrowLeft and ArrowRight, allow to move half-point, i.e. one Peritext point unit, which is not necessarily skipping a whole character. Instead, when pressing RightArrow, it could move from the After anchor of the current character to Before anchor of the next character.
• [ ] In multi-cursor setting, when cursor selections (or carets) overlap, join the cursors.
• [ ] Support for autocompletion popups.
• [ ] cursor event
  • [ ] Fix selection mouse down behavior.
  • [ ] Support model-space locations Point<T>.
  • [ ] Cleanup CursorDetail, len should just be number.
• [ ] Narrow down DOM controller depedency types, pick only what is necessary from event objects.
• [ ] In all cursor edges, in view, render the side specifying to which character anchor point the cursor is attached.
• [ ] Rename both cursor to caret.
• [ ] Add ability to compute .hash for Inline nodes and use that for memoization.
• [ ] Reset pressed key on window resize, this will handle Devtools open event.