refactor(config): parse config values from raw bytes like Zig

Zig parses config values (cli/args.zig, Config.zig field parsers,
config/string.zig) from raw byte slices, and each field type decides
whether it requires UTF-8 (InvalidValue otherwise) or stores bytes. The
port escape-encoded raw bytes into Strings at the line reader and let
fields parse the escaped text, so fields could observe encoding
artifacts; successive audits kept finding such leaks (RV5-RV8).

Field parsers now receive the original bytes: text fields validate UTF-8
where Zig does, byte/path fields store bytes (EncodedOs/OsString). This
resolves all 9 RV8 findings (docs/rewrite/notes/review-rv8-codex.md),
each with a regression test: Windows path conversion fails with
BadPathName instead of substituting U+FFFD; Windows process launch uses
strict UTF-8 like Zig's Command; the WTF-8 decoder accepts paired-
surrogate encodings like Zig; literal U+FDD0 Unicode key triggers;
selection-word-chars and clipboard-codepoint-map reject invalid UTF-8;
font style / codepoint-map family names use original bytes; C title
actions forward bytes; D-Bus new-window/Flatpak conversions match Zig.
Design, sweep and validation: docs/rewrite/notes/final-bytes-refactor.md.

Also moves the bundled iTerm2-Color-Schemes license out of
resources/themes/ so +list-themes no longer lists it as a theme
(output is now byte-identical to Ghostty 1.3.1).

Done by Codex (gpt-6-astra), reviewed and verified by the orchestrator.

Test Plan:
- cargo test --workspace --no-fail-fast (3428 passed, exit 0)
- just check-macos (both), just check-windows, just check-wasm
- +show-config --default --docs, +list-keybinds, +list-actions --docs,
  +list-themes --plain compared with /usr/bin/ghostty

crates/ghostty-core/src/surface/binding.rs

@@ -720,7 +720,7 @@ impl Surface {
                 };
                 // The payload is a config string in the reversible OS-byte
                 // encoding: the pty gets the original bytes.
-                full.extend(ghostty_os::osbytes::config_str_to_bytes(data));
+                full.extend(data.to_bytes());
                 // Zig formats into a fixed 128 byte buffer (`NoSpaceLeft`).
                 if full.len() > 128 {
                     return Err("csi/esc binding sequence too long (max 128 bytes)".into());
@@ -734,10 +734,10 @@ impl Surface {
             Action::Text(data) => {
                 // Decoded bytes: escapes produce UTF-8, everything else is
                 // copied byte for byte (Zig `config/string.zig`).
-                let text = match ghostty_config::string::parse_bytes(data) {
+                let text = match ghostty_config::string::parse_bytes(data.to_bytes()) {
                     Ok(t) => t,
                     Err(err) => {
-                        log::warn!("error parsing text binding text={data} err={err:?}");
+                        log::warn!("error parsing text binding text={data:?} err={err:?}");
                         return Ok(true);
                     }
                 };
@@ -824,9 +824,7 @@ impl Surface {
                     s.handle
                         // The payload is a config string in the reversible
                         // encoding: search for the original bytes.
-                        .send(SearchMessage::ChangeNeedle(
-                            ghostty_os::osbytes::config_str_to_bytes(text),
-                        ));
+                        .send(SearchMessage::ChangeNeedle(text.to_bytes()));
                     s.handle.wakeup();
                 }
             }
@@ -934,15 +932,11 @@ impl Surface {
             }
 
             Action::SetSurfaceTitle(v) => {
-                return Ok(self.perform(RtAction::SetTitle(SetTitle {
-                    title: ghostty_os::osbytes::config_str_to_text(v),
-                })));
+                return Ok(self.perform(RtAction::SetTitle(SetTitle { title: v.clone() })));
             }
 
             Action::SetTabTitle(v) => {
-                return Ok(self.perform(RtAction::SetTabTitle(SetTitle {
-                    title: ghostty_os::osbytes::config_str_to_text(v),
-                })));
+                return Ok(self.perform(RtAction::SetTabTitle(SetTitle { title: v.clone() })));
             }
 
             Action::ClearScreen => {
@@ -1330,7 +1324,7 @@ mod tests {
         // action's EncodedOs decodes back to the same path.
         assert_eq!(path_bytes(&path), path.as_os_str().as_bytes());
         let url = ghostty_os::osbytes::EncodedOs::from_path(&path);
-        assert_eq!(url.to_path(), path);
+        assert_eq!(url.to_path().unwrap(), path);
     }
 
     #[test]