Initial FrameAssistant baseline from the vrdashboard template

Template stripped to the overlay platform (examples, demo UI and Frame
test package removed), renamed to FrameAssistant, and working rules for
the project recorded in CLAUDE.md.

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

docker/native.Dockerfile

@@ -0,0 +1,16 @@
+# Native build environment (any architecture): builds for the machine the container runs on.
+# On the Steam Frame (aarch64) this produces the same self-contained bundle as the x86_64 →
+# aarch64 cross build, without needing a cross toolchain.
+FROM debian:trixie
+
+ENV LANG=C.UTF-8
+
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends \
+        ca-certificates cmake ninja-build pkgconf file patchelf g++ \
+        qt6-base-dev qt6-base-dev-tools qt6-declarative-dev qt6-declarative-dev-tools \
+        libgl-dev libegl-dev libvulkan-dev libxkbcommon-dev \
+        qml6-module-qtquick qml6-module-qtquick-controls qml6-module-qtquick-layouts \
+        qml6-module-qtquick-templates qml6-module-qtqml-workerscript qml6-module-qtquick-window \
+        qml6-module-qttest qt6-qpa-plugins qt6-wayland \
+ && rm -rf /var/lib/apt/lists/*