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/bash.rs

@@ -0,0 +1,129 @@
+//! Bash completions (port of `extra/bash.zig`).
+
+use std::fmt::Write as _;
+
+use ghostty_config::cli_args::FieldKind;
+
+use crate::chunks_bash::{C0, C1, C2, C3, C4, C5, C6};
+use crate::{actions, config_fields, join_names, join_packed};
+
+const COMPGEN_PREFIX: &str = "_compreply compgen -W \"";
+const COMPGEN_SUFFIX: &str = "\" -- \"$cur\"; _add_spaces ;;";
+
+fn is_flag(kind: FieldKind) -> bool {
+    matches!(kind, FieldKind::Bool | FieldKind::OptionalBool)
+}
+
+#[must_use]
+pub fn completions() -> String {
+    let pad1 = "  ";
+    let pad2 = "    ";
+    let pad3 = "      ";
+    let pad4 = "        ";
+    let pad5 = "          ";
+    let mut w = String::new();
+    let fields = config_fields();
+
+    w.push_str(C0);
+    for f in &fields {
+        if is_flag(f.kind) {
+            let _ = writeln!(w, "{pad2}config+=\" '--{} '\"", f.name);
+        } else {
+            let _ = writeln!(w, "{pad2}config+=\" --{}=\"", f.name);
+        }
+    }
+
+    w.push_str(C1);
+    for f in &fields {
+        let _ = write!(w, "{pad3}--{}) ", f.name);
+        if f.name.starts_with("font-family") {
+            w.push_str("_fonts ;;");
+        } else if f.name == "theme" {
+            w.push_str("_themes ;;");
+        } else if f.name == "working-directory" {
+            w.push_str("_dirs ;;");
+        } else if f.kind == FieldKind::RepeatablePath {
+            w.push_str("_files ;;");
+        } else {
+            match f.kind {
+                FieldKind::Enum(names) => {
+                    let _ = write!(w, "{COMPGEN_PREFIX}{}{COMPGEN_SUFFIX}", join_names(names));
+                }
+                FieldKind::Packed(names) => {
+                    let _ = write!(w, "{COMPGEN_PREFIX}{}{COMPGEN_SUFFIX}", join_packed(names));
+                }
+                _ => w.push_str("return ;;"),
+            }
+        }
+        w.push('\n');
+    }
+
+    w.push_str(C2);
+    let acts = actions();
+    for a in acts {
+        let opts = a.option_fields();
+        if opts.is_empty() {
+            continue;
+        }
+        let bash_name = a.name().replace('-', "_");
+        let _ = write!(w, "{pad2}local {bash_name}=\"");
+        for (count, (name, kind)) in opts.iter().enumerate() {
+            if count > 0 {
+                w.push(' ');
+            }
+            if is_flag(*kind) {
+                let _ = write!(w, "'--{name} '");
+            } else {
+                let _ = write!(w, "--{name}=");
+            }
+        }
+        w.push_str(" --help\"\n");
+    }
+
+    w.push_str(C3);
+    for a in acts {
+        let opts = a.option_fields();
+        if opts.is_empty() {
+            continue;
+        }
+        let bash_name = a.name().replace('-', "_");
+        let _ = writeln!(w, "{pad3}+{})", a.name());
+        let _ = writeln!(w, "{pad4}case $prev in");
+        for (name, kind) in &opts {
+            let _ = write!(w, "{pad5}--{name}) ");
+            match kind {
+                FieldKind::Bool => w.push_str("return ;;"),
+                FieldKind::Enum(names) | FieldKind::OptionalEnum(names) => {
+                    let _ = write!(w, "{COMPGEN_PREFIX}{}{COMPGEN_SUFFIX}", join_names(names));
+                }
+                FieldKind::OptionalBool | FieldKind::OptionalOther => {
+                    if *name == "config-file" {
+                        w.push_str("return ;;");
+                    } else {
+                        w.push_str("return;;");
+                    }
+                }
+                _ => {
+                    if *name == "config-file" {
+                        w.push_str("_files ;;");
+                    } else {
+                        w.push_str("return;;");
+                    }
+                }
+            }
+            w.push('\n');
+        }
+        let _ = writeln!(
+            w,
+            "{pad5}*) _compreply compgen -W \"${bash_name}\" -- \"$cur\" ;;"
+        );
+        w.push_str(C4);
+    }
+
+    w.push_str(C5);
+    for a in acts {
+        let _ = writeln!(w, "{pad1}topLevel+=\" +{}\"", a.name());
+    }
+    w.push_str(C6);
+    w
+}