fix: preserve non-UTF-8 bytes in OS, config and CLI layers

Zig treats paths, arguments and environment values as byte slices; the
port converted them lossily in many places. Now (final-Z1.md):
- argv, env (incl. present non-UTF-8 values), HOME, PATH lookup,
  passwd, resources dir, TMPDIR, cgroup, config path canonicalization,
  +validate-config, +list-themes and Zig-string escapes (\xFF) keep raw
  bytes. String-based config values carry bytes via ghostty_os::osbytes,
  a bijective escape (noncharacter U+FDD0 + byte) that leaves all valid
  UTF-8 - including Nerd Font private-use icons - unchanged.
- os/file rlimit fallbacks exist on all targets.
- i18n locale canonicalization is an exact port of libintl's tables
  (e.g. pa-Guru -> pa_IN).
- New ghostty-build-info crate is the single source of version, channel,
  commit and build mode for all consumers.

Test Plan:
- cargo test -p ghostty-os -p ghostty-config -p ghostty-cli
  (incl. randomized osbytes round-trip property tests)

crates/ghostty-config/src/file_load.rs

@@ -59,7 +59,7 @@ pub fn legacy_default_app_support_path() -> Result<String, xdg::Error> {
 #[cfg(target_os = "macos")]
 fn app_support_dir(sub_path: &str) -> Result<String, xdg::Error> {
     ghostty_os::macos::app_support_dir(sub_path)
-        .map(|p| p.to_string_lossy().into_owned())
+        .map(|p| ghostty_os::osbytes::path_to_config_string(&p))
         .map_err(|_| xdg::Error::AppleApiFailed)
 }
 
@@ -159,9 +159,10 @@ impl std::error::Error for OpenFileError {}
 /// if it exists and is non-empty. This also constrains the possible
 /// errors to a smaller set that we can explicitly handle.
 pub fn open(path: &str) -> Result<File, OpenFileError> {
-    assert!(std::path::Path::new(path).is_absolute());
+    assert!(ghostty_os::osbytes::config_str_to_path(path).is_absolute());
 
-    let file = File::open(path).map_err(|err| {
+    // `path` may carry the reversible byte escape of non-UTF-8 names.
+    let file = File::open(ghostty_os::osbytes::config_str_to_os(path)).map_err(|err| {
         if err.kind() == std::io::ErrorKind::NotFound {
             OpenFileError::FileNotFound
         } else {