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-core/src/surface/mouse.rs

@@ -1664,7 +1664,7 @@ impl Surface {
                         sel: link.selection,
                         trim: false,
                     });
-                    let pwd = t.get_pwd().map(|p| String::from_utf8_lossy(p).into_owned());
+                    let pwd = t.get_pwd().map(ghostty_os::osbytes::bytes_to_config_string);
                     resolve_path_for_opening(pwd.as_deref(), &str).unwrap_or(str)
                 }