feat(dist): website data, library installs, XCFramework, dist tarball

Closes the remaining artifact rows of the final audit
(docs/rewrite/notes/final-Z4.md):
- webgen: config.mdx, actions.mdx, commands.mdx (byte-identical to
  Zig's webgen output once its missing stdout flush is added)
- `just install-lib`: libghostty (+ ghostty.h, modulemap) and
  libghostty-vt with versioned symlinks, headers and libghostty-vt.pc
- scripts/xcframework.sh: per-arch builds, lipo and
  xcodebuild -create-xcframework for GhosttyKit (dry-run verified only)
- `just install` builds --profile production so the installed app id is
  com.mitchellh.ghostty; other profiles install the -debug id/name
- `just update-translations`: xgettext/msgmerge pipeline; extracted
  msgids equal upstream's .pot (found and fixed an untranslated string
  in the child-exited banner)
- `just dist` / `distcheck`: versioned source tarball with VERSION and a
  prebuilt GTK resource bundle
- Windows: icon, version resource and DPI/common-controls manifest
  embedded via embed-resource, GUI subsystem

Test Plan:
- just install-lib /tmp/p release all && pkg-config --cflags \
  --libs /tmp/p/share/pkgconfig/libghostty-vt.pc
- just distcheck

scripts/xcframework.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+# Build GhosttyKit.xcframework (macOS only; mirrors build/GhosttyLib.zig
+# `initMacOSUniversal`/`initStatic`, build/GhosttyXCFramework.zig,
+# build/LipoStep.zig and build/XCFrameworkStep.zig).
+#
+# Usage: scripts/xcframework.sh [universal|native] [PROFILE] [OUT]
+#   universal  (default) a universal (arm64 + x86_64, via lipo) macOS static
+#              library, an iOS device library and an iOS simulator library.
+#   native     only the static library for the host macOS architecture.
+#   PROFILE    cargo profile (default production)
+#   OUT        output path (default macos/GhosttyKit.xcframework, like Zig)
+#
+# Each slice is `libghostty.a` (the Rust staticlib already bundles every
+# dependency, so there is no libtool step) plus the `include/` directory with
+# ghostty.h and module.modulemap. Static libraries have no dSYM.
+#
+# DRY_RUN=1 prints the commands instead of running them (usable on any host).
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+target=${1:-universal}
+profile=${2:-production}
+out=${3:-macos/GhosttyKit.xcframework}
+dir=$profile
+[ "$profile" = dev ] && dir=debug
+tdir=${CARGO_TARGET_DIR:-target}
+
+# Config.zig osVersionMin: macOS 13, iOS 17.
+export MACOSX_DEPLOYMENT_TARGET=13.0
+export IPHONEOS_DEPLOYMENT_TARGET=17.0
+
+run() {
+    if [ "${DRY_RUN:-}" = 1 ]; then
+        printf '+'
+        printf ' %q' "$@"
+        printf '\n'
+    else
+        "$@"
+    fi
+}
+
+# Build only the static library for a Rust target triple (the crate also
+# declares a cdylib, which needs no linking for the xcframework).
+build() {
+    run cargo rustc --profile "$profile" -p ghostty-lib --lib --crate-type staticlib --target "$1"
+}
+lib() { echo "$tdir/$1/$dir/libghostty.a"; }
+
+host_arch=$(uname -m)
+case $host_arch in
+arm64 | aarch64) native=aarch64-apple-darwin ;;
+*) native=x86_64-apple-darwin ;;
+esac
+
+args=()
+case $target in
+universal)
+    build aarch64-apple-darwin
+    build x86_64-apple-darwin
+    build aarch64-apple-ios
+    build aarch64-apple-ios-sim
+
+    universal_dir="$tdir/universal-apple-darwin/$dir"
+    run mkdir -p "$universal_dir"
+    run lipo -create -output "$universal_dir/libghostty.a" \
+        "$(lib aarch64-apple-darwin)" "$(lib x86_64-apple-darwin)"
+    args+=(-library "$universal_dir/libghostty.a" -headers crates/ghostty-lib/include)
+    args+=(-library "$(lib aarch64-apple-ios)" -headers crates/ghostty-lib/include)
+    args+=(-library "$(lib aarch64-apple-ios-sim)" -headers crates/ghostty-lib/include)
+    ;;
+native)
+    build "$native"
+    args+=(-library "$(lib "$native")" -headers crates/ghostty-lib/include)
+    ;;
+*)
+    echo "usage: $0 [universal|native] [PROFILE] [OUT]" >&2
+    exit 2
+    ;;
+esac
+
+# The output path is static, so delete the old framework first.
+run rm -rf "$out"
+run xcodebuild -create-xcframework "${args[@]}" -output "$out"