Scaffold NCS firmware project structure

Sets up kvida-os as a freestanding nRF Connect SDK application for the
nRF54L15, pinned to NCS v3.4.0, with a Docker/WSL2 build environment
(toolchain-only image, NCS modules fetched into a separate volume at
first run) and placeholder module directories matching the architecture
described in the kvida meta-repo.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker/Dockerfile

@@ -0,0 +1,21 @@
+# Build-only toolchain image for kvida-os.
+#
+# Provides the Zephyr SDK toolchain, west, CMake, Ninja and Python that
+# NCS builds need. It intentionally does NOT bake in the NCS/Zephyr
+# module tree (nrf/, zephyr/, modules/, ...) fetched by `west update` --
+# that is left to a named volume mounted at /workspace at container run
+# time, so the image stays small and NCS revisions can be bumped without
+# rebuilding it.
+#
+# NOTE: verify this base image tag still exists/is current before relying
+# on it -- it could not be checked against the live registry while
+# writing this Dockerfile.
+FROM ghcr.io/zephyrproject-rtos/zephyr-build:latest
+
+RUN pip3 install --no-cache-dir -U west
+
+WORKDIR /workspace
+
+# TODO: install Nordic's nRF Command Line Tools / nrfutil here if
+# `west flash` should run from inside this container against a J-Link
+# probe forwarded into WSL2 via usbipd-win, instead of from the host.