support width on glyph protocol but only renderer level

[raphamorim]

This branch is completely unpolished but here's the idea:

A Glyph Protocol registration does NOT change a codepoint's logical width: the cell layout stays consistent with system wcwidth so the cursor / selection / copy never desync with a width-unaware consumer (a shell line editor, etc.). The declared width is honoured purely at render time, where the glyph overflows into the following cell(s) in pixels.

It counters #1649 . So if this merges we don't need to drop width from the spec.

Due to the nature of the terminals, we will only have width respected in the render level.

However you may known that if width is 2, then applications should also give a space themselves.

and ofc you can renders as well with width 1: