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/global.rs

@@ -234,7 +234,10 @@ fn init_with(opts: InitOptions, default_logging: Logging) -> &'static GlobalStat
 
         // Setup i18n
         if let Some(v) = resources_dir.app()
-            && let Err(err) = ghostty_os::i18n::init(&v.to_path())
+            && let Err(err) = v
+                .to_path()
+                .map_err(|e| e.to_string())
+                .and_then(|path| ghostty_os::i18n::init(&path).map_err(|e| e.to_string()))
         {
             log::warn!("failed to init i18n, translations will not be available err={err}");
         }

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]

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

@@ -409,21 +409,9 @@ impl Surface {
     }
 }
 
-/// The clipboard codepoint map with string replacements decoded from the
-/// config encoding (a literal `U+FDD0` is restored; bytes that are not
-/// UTF-8 can't be represented in the formatter's text output).
+/// Clipboard replacements are validated UTF-8 by the config field parser.
 fn decode_codepoint_map(list: &[formatter::CodepointMap]) -> Vec<formatter::CodepointMap> {
-    list.iter()
-        .map(|e| formatter::CodepointMap {
-            range: e.range,
-            replacement: match &e.replacement {
-                formatter::Replacement::String(s) => {
-                    formatter::Replacement::String(ghostty_os::osbytes::config_str_to_text(s))
-                }
-                r @ formatter::Replacement::Codepoint(_) => r.clone(),
-            },
-        })
-        .collect()
+    list.to_vec()
 }
 
 #[cfg(test)]
@@ -431,9 +419,8 @@ mod decode_map_tests {
     use super::*;
 
     #[test]
-    fn string_replacements_are_decoded() {
-        let enc = ghostty_os::osbytes::valid_str_to_config_string("a\u{fdd0}");
-        assert_ne!(enc, "a\u{fdd0}");
+    fn string_replacements_are_plain_text() {
+        let enc = "a\u{fdd0}".to_owned();
         let list = [formatter::CodepointMap {
             range: [1, 2],
             replacement: formatter::Replacement::String(enc),

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

@@ -55,7 +55,7 @@ impl DerivedConfig {
         let mut links = Vec::with_capacity(config.link.links.len());
         for link in &config.link.links {
             links.push(Link {
-                regex: Regex::new(&ghostty_os::osbytes::config_str_to_text(&link.regex))?,
+                regex: Regex::new(&link.regex)?,
                 action: link.action,
                 highlight: link.highlight,
             });

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

@@ -24,6 +24,7 @@ use ghostty_input::{
     key_encode,
 };
 use ghostty_inspector as inspector;
+use ghostty_os::osbytes::EncodedOs;
 use ghostty_terminal::terminal::{MouseEvents, ScrollViewport, Terminal};
 use ghostty_termio::message::Message as IoMessage;
 use ghostty_vt::{modes::Mode, mouse_shape::MouseShape};
@@ -40,7 +41,7 @@ pub enum SetRoot {
     /// The root keybinding set.
     Root,
     /// A named key table.
-    Table(String),
+    Table(EncodedOs),
 }
 
 /// The currently active key sequence: the set it started in plus the
@@ -54,7 +55,7 @@ pub struct SequencePath {
 /// An entry of the key table stack.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct TableEntry {
-    pub name: String,
+    pub name: EncodedOs,
     pub once: bool,
 }
 
@@ -796,12 +797,16 @@ impl Surface {
     /// Activate a key table by name (Zig: `activate_key_table[_once]`).
     /// Returns whether the table was activated.
     #[allow(dead_code, clippy::unnecessary_wraps)] // used by the binding-actions module
-    pub(crate) fn activate_key_table(&self, name: &str, once: bool) -> Result<bool, CoreError> {
+    pub(crate) fn activate_key_table(
+        &self,
+        name: &EncodedOs,
+        once: bool,
+    ) -> Result<bool, CoreError> {
         let cfg = self.cfg();
 
         // Look up the table in our config
         if root_set(&cfg, &SetRoot::Table(name.to_owned())).is_none() {
-            log::debug!("key table not found: {name}");
+            log::debug!("key table not found: {name:?}");
             return Ok(false);
         }
 
@@ -810,14 +815,14 @@ impl Surface {
 
             // If this is the same table as is currently active, then do
             // nothing.
-            if kb.table_stack.last().is_some_and(|t| t.name == name) {
-                log::debug!("ignoring duplicate activate table: {name}");
+            if kb.table_stack.last().is_some_and(|t| &t.name == name) {
+                log::debug!("ignoring duplicate activate table: {name:?}");
                 return Ok(false);
             }
 
             // If we're already at the max, ignore it.
             if kb.table_stack.len() >= MAX_ACTIVE_KEY_TABLES {
-                log::info!("ignoring activate table, max depth reached: {name}");
+                log::info!("ignoring activate table, max depth reached: {name:?}");
                 return Ok(false);
             }
 
@@ -831,7 +836,7 @@ impl Surface {
         // Notify the UI.
         self.perform(RtAction::KeyTable(KeyTable::Activate(name.to_owned())));
 
-        log::debug!("key table activated: {name}");
+        log::debug!("key table activated: {name:?}");
         Ok(true)
     }
 

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

@@ -459,10 +459,7 @@ impl Surface {
             // don't leak GHOSTTY_LOG to any subprocesses
             env.remove("GHOSTTY_LOG");
 
-            let mut ecfg = exec::Config::new(
-                env,
-                ghostty_os::osbytes::EncodedOs::from_encoded(config.term.clone()),
-            );
+            let mut ecfg = exec::Config::new(env, config.term.clone());
             ecfg.command = command.clone();
             ecfg.env_override = config.env.clone();
             ecfg.shell_integration = config.shell_integration;
@@ -607,7 +604,7 @@ impl Surface {
             rt_app.perform_action(
                 Target::Surface(id),
                 RtAction::SetTitle(SetTitle {
-                    title: ghostty_os::osbytes::config_str_to_text(title),
+                    title: title.clone(),
                 }),
             );
         } else if config.xdg_terminal_exec
@@ -620,7 +617,7 @@ impl Surface {
             rt_app.perform_action(
                 Target::Surface(id),
                 RtAction::SetTitle(SetTitle {
-                    title: ghostty_os::osbytes::config_str_to_text(&cmd.string()),
+                    title: ghostty_os::osbytes::EncodedOs::from_encoded(cmd.string()),
                 }),
             );
         } else if let Some(cmd) = &command {
@@ -636,7 +633,7 @@ impl Surface {
                 rt_app.perform_action(
                     Target::Surface(id),
                     RtAction::SetTitle(SetTitle {
-                        title: ghostty_os::osbytes::config_str_to_text(first),
+                        title: first.clone(),
                     }),
                 );
             }
@@ -872,8 +869,8 @@ impl Surface {
                 }
 
                 let end = buf.iter().position(|&b| b == 0).unwrap_or(buf.len());
-                let title = String::from_utf8_lossy(&buf[..end]).into_owned();
-                log::debug!("changing title \"{title}\"");
+                let title = ghostty_os::osbytes::EncodedOs::from_bytes(&buf[..end]);
+                log::debug!("changing title {title:?}");
                 self.perform(RtAction::SetTitle(SetTitle { title }));
             }
 
@@ -885,11 +882,14 @@ impl Surface {
 
                 let title = self.rt_surface.get_title();
                 let data = match style {
-                    ghostty_apprt::surface::ReportTitleStyle::Csi21T => {
-                        format!("\x1b]l{}\x1b\\", title.unwrap_or_default())
-                    }
+                    ghostty_apprt::surface::ReportTitleStyle::Csi21T => [
+                        b"\x1b]l".as_slice(),
+                        &title.unwrap_or_default().to_bytes(),
+                        b"\x1b\\",
+                    ]
+                    .concat(),
                 };
-                self.queue_io(IoMessage::write_req(data.as_bytes()));
+                self.queue_io(IoMessage::write_req(data.as_slice()));
             }
 
             Message::ColorChange(change) => {
@@ -1306,7 +1306,7 @@ impl Surface {
         // configured title.
         if let Some(title) = &config.title {
             self.perform(RtAction::SetTitle(SetTitle {
-                title: ghostty_os::osbytes::config_str_to_text(title),
+                title: title.clone(),
             }));
         }
 

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

@@ -2543,8 +2543,8 @@ mod tests {
         // The OSC 7 pwd is raw bytes.
         let pwd = dir.as_os_str().as_bytes().to_vec();
         let t = open_link_target(Some(&pwd), "file.txt");
-        assert_eq!(t.to_path(), dir.join("file.txt"));
-        assert!(t.to_path().exists());
+        assert_eq!(t.to_path().unwrap(), dir.join("file.txt"));
+        assert!(t.to_path().unwrap().exists());
     }
 
     #[test]