feat(cli): port ghostty +action CLI commands

Ports ZIG/src/cli into ghostty-cli: action detection/dispatch with
per-action --help, and the actions help, version, list-actions,
list-colors, list-keybinds, list-themes (plain listing plus an
interactive ratatui browser mirroring Ghostty's libvaxis UI),
show-config, validate-config, edit-config, crash-report (listing),
ssh-cache and boo (235 embedded frames).

Verified byte-for-byte against the installed Ghostty 1.3.1 for stdout,
stderr and exit codes of most actions, incl. tty output in a pty at
widths 20-200. Known differences: +list-colors --plain prints all 782
colors (Ghostty truncates at 617 because it never flushes), +version
has placeholder build info until build_info::set is wired up.

Deferred: list-fonts, show-face (need font discovery integration) and
new-window (needs GTK IPC); they return NotYetAvailable for now.

Test Plan:
- cargo test -p ghostty-cli (86 tests)
- cargo run -p ghostty-cli --example cli -- +list-keybinds --plain
  and diff against `ghostty +list-keybinds --plain`

crates/ghostty-cli/src/edit_config.rs

@@ -0,0 +1,112 @@
+//! `+edit-config` (ZIG/src/cli/edit_config.zig).
+
+use std::io::Write;
+use std::os::unix::process::CommandExt;
+
+use ghostty_config::config::Config;
+
+use crate::error::Error;
+
+pub use crate::options::NoOptions as Options;
+
+/// The `edit-config` command opens the Ghostty configuration file in the
+/// editor specified by the `$VISUAL` or `$EDITOR` environment variables.
+///
+/// IMPORTANT: This command will not reload the configuration after
+/// editing. You will need to manually reload the configuration using the
+/// application menu, configured keybind, or by restarting Ghostty. We
+/// plan to auto-reload in the future, but Ghostty isn't capable of
+/// this yet.
+///
+/// The filepath opened is the default user-specific configuration
+/// file, which is typically located at `$XDG_CONFIG_HOME/ghostty/config.ghostty`.
+/// On macOS, this may also be located at
+/// `~/Library/Application Support/com.mitchellh.ghostty/config.ghostty`.
+/// On macOS, whichever path exists and is non-empty will be prioritized,
+/// prioritizing the Application Support directory if neither are
+/// non-empty.
+///
+/// This command prefers the `$VISUAL` environment variable over `$EDITOR`,
+/// if both are set. If neither are set, it will print an error
+/// and exit.
+pub fn run(args: &[String]) -> Result<u8, Error> {
+    let mut stderr = std::io::stderr().lock();
+
+    let mut opts = Options;
+    crate::parse_options(&mut opts, args)?;
+
+    let result = run_inner(&mut stderr);
+    // Flushing *shouldn't* fail but...
+    let _ = stderr.flush();
+    result
+}
+
+/// Pick the editor from `$VISUAL` then `$EDITOR` (empty values are skipped).
+#[must_use]
+pub fn find_editor() -> Option<String> {
+    // VISUAL vs. EDITOR: https://unix.stackexchange.com/questions/4859/visual-vs-editor-what-s-the-difference
+    for var in ["VISUAL", "EDITOR"] {
+        if let Some(v) = ghostty_os::getenv(var) {
+            if !v.is_empty() {
+                return Some(v);
+            }
+        }
+    }
+    None
+}
+
+fn run_inner(stderr: &mut dyn Write) -> Result<u8, Error> {
+    // We load the configuration once because that will write our
+    // default configuration files to disk. We don't use the config.
+    let _config = Config::load()?;
+
+    // Find the preferred path.
+    let path = ghostty_config::file_load::preferred_default_file_path()
+        .map_err(|e| Error::Other(e.to_string()))?;
+
+    // Get our editor
+    let Some(editor) = find_editor() else {
+        // If we don't have `$EDITOR` set then we can't do anything
+        // but we can still print a helpful message.
+        write!(
+            stderr,
+            "The $EDITOR or $VISUAL environment variable is not set or is empty.\n\
+             This environment variable is required to edit the Ghostty configuration\n\
+             via this CLI command.\n\
+             \n\
+             Please set the environment variable to your preferred terminal\n\
+             text editor and try again.\n\
+             \n\
+             If you prefer to edit the configuration file another way,\n\
+             you can find the configuration file at the following path:\n\
+             \n"
+        )?;
+
+        // Output the path using the OSC8 sequence so that it is linked.
+        writeln!(stderr, "\x1b]8;;file://{path}\x1b\\{path}\x1b]8;;\x1b\\")?;
+        return Ok(1);
+    };
+
+    // Flush before exec so no output is lost.
+    let _ = stderr.flush();
+    let err = std::process::Command::new(&editor).arg(&path).exec();
+
+    // If we reached this point then exec failed.
+    let err = match err.kind() {
+        std::io::ErrorKind::NotFound => "error.FileNotFound".to_string(),
+        std::io::ErrorKind::PermissionDenied => "error.AccessDenied".to_string(),
+        _ => err.to_string(),
+    };
+    write!(
+        stderr,
+        "Failed to execute the editor. Error code={err}.\n\
+         \n\
+         This is usually due to the executable path not existing, invalid\n\
+         permissions, or the shell environment not being set up\n\
+         correctly.\n\
+         \n\
+         Editor: {editor}\n\
+         Path: {path}\n"
+    )?;
+    Ok(1)
+}