Add version (std.SemanticVersion) to the terminal build options so that
the terminal module has access to the application version at comptime.
The add() function breaks it out into version_string, version_major,
version_minor, version_patch, and version_build terminal options.
On the C API side, five new GhosttyBuildInfo variants expose these
through ghostty_build_info(). String values use GhosttyString; numeric
values use size_t. When no build metadata is present, version_build
returns a zero-length string.
The c-vt-build-info example is updated to query and print all version
fields.
Add a new C API function ghostty_build_info() that exposes compile-time
build options to library consumers. This allows callers to query whether
SIMD, Kitty graphics protocol, and tmux control mode support were
enabled at build time.
