release: add ARM64 release build script; installer knows its pinned release

- scripts/build-release.sh WORKDIR VERSION fetches SHA-256-pinned SDL3
  3.2.16 and OpenVR SDK 2.15.6, builds audio-only SDL3 and FrameYap, runs
  the tests, then stages and packages an external-runtime archive.
- RELEASE_VERSION (set in a tagged release commit) makes the attended
  installer ask only y/n: install this release from GitHub, the speech
  model, the CPU runtime. Flag-driven binary installs default to it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/build-release.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+# Build a FrameYap native-only release archive on Linux ARM64.
+#
+#   sh scripts/build-release.sh WORKDIR VERSION
+#
+# Downloads the pinned SDL3 and OpenVR SDK sources into WORKDIR (SHA-256
+# checked), builds audio-only SDL3 and FrameYap, runs the tests, then stages
+# and packages WORKDIR/out/frameyap-VERSION-linux-aarch64.tar.gz(.sha256).
+# No ASR runtime, model, Kestrel or Torch is downloaded or bundled.
+set -eu
+
+SDL_VERSION=3.2.16
+SDL_URL="https://github.com/libsdl-org/SDL/releases/download/release-$SDL_VERSION/SDL3-$SDL_VERSION.tar.gz"
+SDL_SHA256=6340e58879b2d15830c8460d2f589a385c444d1faa2a4828a9626c7322562be8
+OPENVR_VERSION=2.15.6
+OPENVR_URL="https://github.com/ValveSoftware/openvr/archive/refs/tags/v$OPENVR_VERSION.tar.gz"
+OPENVR_SHA256=e184cb625010fab7043a9d5e1e000fdeb3067a152bb3169ef53f64dfac37164c
+
+if [ "$#" -ne 2 ]; then
+    echo "usage: sh scripts/build-release.sh WORKDIR VERSION" >&2
+    exit 2
+fi
+case "$1" in /*) work=$1 ;; *) work=$(pwd)/$1 ;; esac
+version=$2
+source=$(cd "$(dirname "$0")/.." && pwd)
+[ "$(uname -s)-$(uname -m)" = Linux-aarch64 ] || { echo "release archives are built on Linux aarch64" >&2; exit 1; }
+if [ -e "$work/out/frameyap-$version-linux-aarch64.tar.gz" ]; then
+    echo "release already exists in $work/out" >&2
+    exit 1
+fi
+mkdir -p "$work/downloads"
+
+fetch() { # url sha256 destination
+    if [ ! -f "$3" ]; then
+        curl --fail --silent --show-error --location --proto =https --output "$3.part" "$1"
+        mv "$3.part" "$3"
+    fi
+    echo "$2  $3" | sha256sum -c - >/dev/null || { echo "SHA-256 mismatch: $3" >&2; exit 1; }
+}
+fetch "$SDL_URL" "$SDL_SHA256" "$work/downloads/SDL3-$SDL_VERSION.tar.gz"
+fetch "$OPENVR_URL" "$OPENVR_SHA256" "$work/downloads/openvr-$OPENVR_VERSION.tar.gz"
+
+rm -rf "$work/src" "$work/sdl-build" "$work/sdl" "$work/build" "$work/stage"
+mkdir -p "$work/src" "$work/out"
+tar -xzf "$work/downloads/SDL3-$SDL_VERSION.tar.gz" -C "$work/src"
+tar -xzf "$work/downloads/openvr-$OPENVR_VERSION.tar.gz" -C "$work/src"
+openvr=$work/src/openvr-$OPENVR_VERSION
+
+# Audio only; PipeWire/Pulse/ALSA backends are loaded at runtime when present.
+cmake -S "$work/src/SDL3-$SDL_VERSION" -B "$work/sdl-build" -DCMAKE_BUILD_TYPE=Release \
+    -DCMAKE_INSTALL_PREFIX="$work/sdl" -DCMAKE_INSTALL_LIBDIR=lib \
+    -DSDL_SHARED=ON -DSDL_STATIC=OFF -DSDL_TESTS=OFF -DSDL_EXAMPLES=OFF -DSDL_VIDEO=OFF \
+    -DSDL_AUDIO=ON -DSDL_PIPEWIRE=ON -DSDL_PULSEAUDIO=ON -DSDL_ALSA=ON
+cmake --build "$work/sdl-build" --parallel
+cmake --install "$work/sdl-build"
+
+PKG_CONFIG_PATH="$work/sdl/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}" \
+cmake -S "$source" -B "$work/build" -DCMAKE_BUILD_TYPE=Release -DFRAMEYAP_VERSION="$version" \
+    -DFRAMEYAP_NATIVE=ON -DFRAMEYAP_UI_TESTS=ON -DOPENVR_ROOT="$openvr" \
+    -DOPENVR_LIBRARY="$openvr/lib/linuxarm64/libopenvr_api.so"
+cmake --build "$work/build" --parallel
+ctest --test-dir "$work/build" --output-on-failure
+
+python3 "$source/scripts/stage-native.py" --build "$work/build" --destination "$work/stage" \
+    --openvr-library "$openvr/lib/linuxarm64/libopenvr_api.so" --openvr-license "$openvr/LICENSE" \
+    --sdl-library "$work/sdl/lib/libSDL3.so.0" --sdl-license "$work/src/SDL3-$SDL_VERSION/LICENSE.txt"
+revision=$(python3 -c 'import json,sys; print(json.load(open(sys.argv[1]))["model"]["revision"])' \
+    "$source/assets/backends/redux.json")
+python3 "$source/scripts/package-release.py" --stage "$work/stage" --output "$work/out" \
+    --version "$version" --arch linux-aarch64 --model-revision "$revision" --external-runtime