The terminal.Stream next/nextSlice functions can now no longer fail.
All prior failure modes were fully isolated in the handler `vt`
callbacks. As such, vt callbacks are now required to not return an error
and handle their own errors somehow.
Allowing streams to be fallible before was an incorrect design. It
caused problematic scenarios like in `nextSlice` early terminating
processing due to handler errors. This should not be possible.
There is no safe way to bubble up vt errors through the stream because
if nextSlice is called and multiple errors are returned, we can't
coalesce them. We could modify that to return a partial result but its
just more work for stream that is unnecessary. The handler can do all of
this.
This work was discovered due to cleanups to prepare for more C APIs.
Less errors make C APIs easier to implement! And, it helps clean up our
Zig, too.
Fixes#9957
Our `Page.getRowAndCell` uses a _page-relative_ x/y coordinate system
and we were passing in viewport x/y. This has the possibility to leading
to all sorts of bugs, including the crash found in #9957 but also simply
reading the wrong cell even in single-page scenarios.
This fixes memory corruption where future matches on a fully dirty row
would write highlights out of bounds. It was easy to reproduce in debug
by searching for `$` in `ghostty +boo`
This makes `cursorStyle` utilize `RenderState` to determine the
appropriate cursor style. This moves the cursor style logic outside the
critical area, although it was cheap to begin with.
This always removes `viewport_is_bottom` which had no practical use.
