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-lib/src/action_c.rs

@@ -36,7 +36,14 @@ pub struct Keep {
 impl Keep {
     /// A NUL terminated copy of `s` (interior NULs are dropped).
     fn cstr(&mut self, s: &str) -> *const c_char {
-        let c = CString::new(s.replace('\0', "")).unwrap_or_default();
+        self.cstr_bytes(s.as_bytes())
+    }
+
+    /// [`Keep::cstr`] for raw bytes.
+    fn cstr_bytes(&mut self, s: &[u8]) -> *const c_char {
+        let mut s = s.to_vec();
+        s.retain(|&b| b != 0);
+        let c = CString::new(s).unwrap_or_default();
         let ptr = c.as_ptr();
         // The heap buffer of a CString doesn't move when the Vec grows.
         self.strings.push(c);
@@ -123,7 +130,9 @@ pub fn action_to_c(action: &Action, keep: &mut Keep) -> ghostty_action_s {
         Action::SetTitle(t) => v.set_title.title = keep.cstr(&t.title),
         Action::SetTabTitle(t) => v.set_tab_title.title = keep.cstr(&t.title),
         Action::PromptTitle(p) => v.prompt_title = *p as c_int,
-        Action::Pwd(p) => v.pwd.pwd = keep.cstr(&p.pwd),
+        Action::Pwd(p) => {
+            v.pwd.pwd = keep.cstr_bytes(&ghostty_os::osbytes::config_str_to_bytes(&p.pwd));
+        }
         Action::MouseShape(s) => v.mouse_shape = *s as c_int,
         Action::MouseVisibility(m) => v.mouse_visibility = *m as c_int,
         Action::MouseOverLink(l) => {