Introduces static path methods and a reworked context API that makes
things generally cleaner.
This update incidentally fixed a bug we had before where the corner
triangle shade characters were drawn solid rather than medium shade.
- Make canvas geometry primitives generic, use `Rect(u32)` for `rect`
function, so that we don't have to worry about negatives or rounding.
- Make `Quads` struct packed just in case it gets non-comptime use in
the future.
- Clarify comment on why we're discarding out of range pixels + runtime
unreachable for any other type of error which we shouldn't ever see.
- Move z2d import above in-tree imports.
More complete coverage of the Symbols For Legacy Computing block,
including characters from Unicode 16.0.
Pixman and the web canvas impl for Canvas have been removed in favor of
z2d for drawing, since it has a nicer API with more powerful methods,
and is in Zig with no specific platform optimizations so should compile
to wasm no problem.
