feat(dist): generate completions, editor syntax, man pages, translations

Ports Ghostty's build-data helpers (main_build_data.zig, src/extra/*,
build/mdgen) as the ghostty-build-data binary: bash/zsh/fish
completions, Vim syntax/ftdetect/ftplugin/compiler, Sublime syntax (also
used by bat), terminfo source and ghostty(1)/ghostty(5) markdown. With
the version set to the installed 1.3.1-arch2, all generated files are
byte-identical to the installed Ghostty's.

- `just docs` renders man pages and HTML with pandoc.
- po/: Ghostty's 29 translation catalogs; `just locales` compiles them
  into the com.mitchellh.ghostty gettext domain.
- `just install PREFIX FLATPAK SYSTEM_PACKAGE` installs everything incl.
  terminfo text/termcap outputs and mirrors GhosttyResources.zig install
  modes (Flatpak D-Bus template without systemd; lib/systemd/user for
  system packages).
- Build metadata (version, tip/stable channel, commit, build mode) is
  derived at build time like build_config.zig; GTK/libadwaita
  compile-time versions come from pkg-config instead of constants.

Test Plan:
- cargo run -p ghostty-build-data -- +bash | diff - \
  /usr/share/bash-completion/completions/ghostty (same for zsh/fish/vim)
- just install /tmp/prefix

crates/ghostty-build-data/src/fish.rs

@@ -0,0 +1,146 @@
+//! Fish completions (port of `extra/fish.zig`).
+
+use std::fmt::Write as _;
+
+use ghostty_cli::Action;
+use ghostty_config::cli_args::FieldKind;
+
+use crate::{actions, config_fields, join_names, join_packed};
+
+#[must_use]
+pub fn completions() -> String {
+    let mut w = String::new();
+    let acts = actions();
+    let plus = |sep: &str| {
+        acts.iter()
+            .map(|a| format!("+{}", a.name()))
+            .collect::<Vec<_>>()
+            .join(sep)
+    };
+
+    let _ = writeln!(w, "set -l commands \"{}\"", plus(" "));
+    w.push_str("complete -c ghostty -f\n");
+    w.push_str("complete -c ghostty -s e -l help -f\n");
+    w.push_str(
+        "complete -c ghostty -n \"not __fish_seen_subcommand_from $commands\" -l version -f\n",
+    );
+
+    for f in config_fields() {
+        w.push_str("complete -c ghostty -n \"not __fish_seen_subcommand_from $commands\" -l ");
+        w.push_str(f.name);
+        w.push_str(if f.kind == FieldKind::Bool {
+            " "
+        } else {
+            " -r"
+        });
+        if f.name.starts_with("font-family") {
+            w.push_str(" -f  -a \"(ghostty +list-fonts | grep '^[A-Z]')\"");
+        } else if f.name == "theme" {
+            w.push_str(" -f -a \"(ghostty +list-themes | sed -E 's/^(.*) \\(.*\\$/\\1/')\"");
+        } else if f.name == "working-directory" {
+            w.push_str(" -f -k -a \"(__fish_complete_directories)\"");
+        } else {
+            w.push_str(if f.kind == FieldKind::RepeatablePath {
+                " -F"
+            } else {
+                " -f"
+            });
+            match f.kind {
+                FieldKind::Enum(names) => {
+                    let _ = write!(w, " -a \"{}\"", join_names(names));
+                }
+                FieldKind::Packed(names) => {
+                    let _ = write!(w, " -a \"{}\"", join_packed(names));
+                }
+                _ => {}
+            }
+        }
+        if !f.help.is_empty() {
+            let _ = write!(w, " -d \"{}\"", get_description(&f.help));
+        }
+        w.push('\n');
+    }
+
+    let _ = writeln!(
+        w,
+        "complete -c ghostty -n \"string match -q -- '+*' (commandline -pt)\" -f -a \"{}\"",
+        plus(" ")
+    );
+
+    for a in acts {
+        if matches!(a, Action::Help | Action::Version) {
+            continue;
+        }
+        for (name, kind) in a.option_fields() {
+            let _ = write!(
+                w,
+                "complete -c ghostty -n \"__fish_seen_subcommand_from +{}\" -l {name}",
+                a.name()
+            );
+            if kind != FieldKind::Bool {
+                w.push_str(" -r");
+            }
+            w.push_str(if name == "config-file" { " -F" } else { " -f" });
+            match kind {
+                FieldKind::Enum(names) | FieldKind::OptionalEnum(names) => {
+                    let _ = write!(w, " -a \"{}\"", join_names(names));
+                }
+                _ => {}
+            }
+            w.push('\n');
+        }
+    }
+    w
+}
+
+/// First sentence of the help text on one line, with quotes escaped
+/// (Zig: `getDescription`).
+#[must_use]
+pub fn get_description(help: &str) -> String {
+    let b = help.as_bytes();
+    let mut out = Vec::with_capacity(b.len() * 2);
+    let mut prev_was_space = false;
+    for (i, &c) in b.iter().enumerate() {
+        match c {
+            b'.' => {
+                out.push(b'.');
+                if i + 1 >= b.len() {
+                    break;
+                }
+                let next = b[i + 1];
+                if next == b' ' || next == b'\n' {
+                    break;
+                }
+            }
+            b'\n' => {
+                if !prev_was_space && !out.is_empty() {
+                    out.push(b' ');
+                    prev_was_space = true;
+                }
+            }
+            b'"' => {
+                out.extend_from_slice(b"\\\"");
+                prev_was_space = false;
+            }
+            _ => {
+                out.push(c);
+                prev_was_space = c == b' ';
+            }
+        }
+    }
+    String::from_utf8_lossy(&out).into_owned()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn get_description_test() {
+        let input = "First sentence with \"quotes\"\nand newlines. Second sentence.";
+        assert_eq!(
+            get_description(input),
+            "First sentence with \\\"quotes\\\" and newlines."
+        );
+    }
+}