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-termio/src/stream_handler.rs

@@ -86,7 +86,7 @@ use crate::{
 };
 
 /// `build_config.version_string`.
-pub const VERSION_STRING: &str = "1.3.1";
+pub const VERSION_STRING: &str = ghostty_build_info::VERSION_STRING;
 
 /// The long-lived state of the handler (everything but the terminal).
 pub struct HandlerState {
@@ -1693,7 +1693,11 @@ mod tests {
     fn xtversion() {
         let mut h = Harness::new();
         h.feed(b"\x1b[>q");
-        assert_eq!(b"\x1bP>|ghostty 1.3.1\x1b\\".as_slice(), h.written());
+        let want = format!(
+            "\x1bP>|ghostty {}\x1b\\",
+            ghostty_build_info::VERSION_STRING
+        );
+        assert_eq!(want.as_bytes(), h.written());
     }
 
     #[test]