fix: Windows core build, embedded init, byte-exact paths, version info

Closes the remaining core/lib/termio/GTK rows (final-Z2.md):
- ghostty-core compiles for Windows (Unix-only exec fields and file
  modes gated); checked with cargo check --target x86_64-pc-windows-gnu.
- Embedded init: ensure_locale, SIGPIPE ignored in ghostty_init for
  C/Swift hosts, Apple crash tags; the argv passed to ghostty_init feeds
  ghostty_config_load_cli_args; ghostty_config_load_file accepts
  non-UTF-8 paths.
- OSC 7 pwd, embedded surface cwd/command/env/initial input,
  ghostty_surface_text and GTK file drops keep raw bytes.
- XTVERSION, TERM_PROGRAM_VERSION, the About dialog and crash metadata
  use ghostty_build_info instead of hardcoded versions.

Test Plan:
- cargo test --workspace (3327 passed)
- cargo clippy --workspace --all-targets -- -D warnings

crates/ghostty-apprt-gtk/src/class/window.rs

@@ -1662,7 +1662,7 @@ impl Window {
                 .application_name(name)
                 .developer_name(tr("Ghostty Developers"))
                 .application_icon(icon)
-                .version(env!("CARGO_PKG_VERSION"))
+                .version(ghostty_build_info::VERSION_STRING)
                 .issue_url("https://github.com/ghostty-org/ghostty/issues")
                 .website(website)
                 .build();
@@ -1675,7 +1675,7 @@ impl Window {
                     ("program-name", &name),
                     ("logo-icon-name", &icon),
                     ("title", &tr("About Ghostty")),
-                    ("version", &env!("CARGO_PKG_VERSION")),
+                    ("version", &ghostty_build_info::VERSION_STRING),
                     ("website", &website),
                 ],
             );