fix: systematic byte fidelity for config strings and RV7 gaps

Resolves the 9 gap groups in docs/rewrite/notes/review-rv7-codex.md and
audits every string-typed config field against its consumers
(field -> consumers -> decode status table in final-Z9.md):
- Windows EnvMap keys use a port of Zig's nls.zig uppercase table
  (upcaseW); Windows locale init follows Zig's chain (setlocale +
  _putenv_s); malformed WTF-8 now fails process launch conversions like
  Zig instead of substituting U+FFFD; kitty file paths convert WTF-8.
- bash --rcfile/--init-file, configured TERM and inherited GTK LANG
  keep their original bytes.
- C API clipboard completion and ghostty_surface_binding_action take
  bytes; complete_clipboard_request is byte-typed through the core.
- text:/csi:/esc: bindings, enquiry-response, input = path:, embedded
  initial_input, search needles, titles, link regexes, clipboard
  codepoint map, command palette text and GTK font/namespace values
  decode the escape encoding before use.

Remaining by design: D-Bus a{ss} values and +new-window arguments are
UTF-8 by D-Bus type. C API key/preedit text follows separately.

Test Plan:
- cargo test --workspace
- just check-macos (both), just check-windows, just check-wasm

crates/ghostty-cli/src/show_face.rs

@@ -100,7 +100,9 @@ fn run_args(
             continue;
         }
         if FIELDS.contains(&d.key.as_str()) {
-            writeln!(stderr, "config error: {d}")?;
+            stderr.write_all(&ghostty_os::osbytes::config_str_to_bytes(&format!(
+                "config error: {d}\n"
+            )))?;
             exit = true;
         }
     }
@@ -133,7 +135,9 @@ fn run_args(
         {
             continue;
         }
-        writeln!(stderr, "config error: {d}")?;
+        stderr.write_all(&ghostty_os::osbytes::config_str_to_bytes(&format!(
+            "config error: {d}\n"
+        )))?;
     }
 
     let font_grid_set = match SharedGridSet::new() {

crates/ghostty-cli/src/validate_config.rs

@@ -53,7 +53,11 @@ fn run_inner(opts: &Options, stdout: &mut dyn Write) -> Result<u8, Error> {
 
     if !cfg.diagnostics.items().is_empty() {
         for diag in cfg.diagnostics.items() {
-            writeln!(stdout, "{diag}")?;
+            // Diagnostics embed config values in the reversible byte
+            // encoding; print the original bytes.
+            stdout.write_all(&ghostty_os::osbytes::config_str_to_bytes(&format!(
+                "{diag}\n"
+            )))?;
         }
         return Ok(1);
     }
@@ -105,6 +109,27 @@ mod tests {
         );
     }
 
+    #[cfg(unix)]
+    #[test]
+    fn diagnostics_print_original_bytes() {
+        use std::os::unix::ffi::OsStrExt;
+        let tmp = tempfile::tempdir().unwrap();
+        let path = tmp.path().join("config");
+        std::fs::write(&path, b"bad\xffkey = 1\n").unwrap();
+        let opts = Options {
+            config_file: Some(path.to_string_lossy().into_owned()),
+        };
+        let mut out = Vec::new();
+        assert_eq!(1, run_inner(&opts, &mut out).unwrap());
+        assert!(
+            out.windows(7).any(|w| w == b"bad\xffkey"),
+            "{:?}",
+            String::from_utf8_lossy(&out)
+        );
+        assert!(!out.contains(&0xef), "no escape encoding in the output");
+        let _ = path.as_os_str().as_bytes();
+    }
+
     #[test]
     fn validate_missing_file_is_error() {
         let opts = Options {