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-apprt-gtk/build.rs

@@ -16,7 +16,7 @@ const CSS: &[&str] = &[
     "style-hc.css",
     "style-hc-dark.css",
 ];
-// (major, minor, name). The inspector / imgui blueprints are deferred.
+// (major, minor, name).
 const BLUEPRINTS: &[(u32, u32, &str)] = &[
     (1, 0, "clipboard-confirmation-dialog"),
     (1, 4, "clipboard-confirmation-dialog"),
@@ -36,9 +36,31 @@ const BLUEPRINTS: &[(u32, u32, &str)] = &[
     (1, 5, "title-dialog"),
     (1, 5, "window"),
     (1, 5, "command-palette"),
+    (1, 5, "imgui-widget"),
+    (1, 5, "inspector-widget"),
+    (1, 5, "inspector-window"),
 ];
 
+/// Emits `GHOSTTY_<name>_VERSION` with the version of a library as reported
+/// by pkg-config (the headers we compile against; Zig reads the same values
+/// from the C headers). Falls back to the feature level we require.
+fn emit_pkg_version(env_name: &str, pkg: &str, fallback: &str) {
+    println!("cargo:rerun-if-env-changed=PKG_CONFIG_PATH");
+    let version = Command::new("pkg-config")
+        .args(["--modversion", pkg])
+        .output()
+        .ok()
+        .filter(|o| o.status.success())
+        .and_then(|o| String::from_utf8(o.stdout).ok())
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(|| fallback.to_string());
+    println!("cargo:rustc-env={env_name}={version}");
+}
+
 fn main() {
+    emit_pkg_version("GHOSTTY_GTK_VERSION", "gtk4", "4.14.0");
+    emit_pkg_version("GHOSTTY_ADW_VERSION", "libadwaita-1", "1.5.0");
     let manifest = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
     let out = PathBuf::from(std::env::var("OUT_DIR").unwrap());
     let res = manifest.join("resources");