Rebuild firmware scaffold for ESP32-C6/ESP-IDF, replacing NCS/Zephyr

The product pivoted away from a Matter-first nRF54L15 device to an
ESP32-C6/ESP-IDF/C++17 platform where behaviour is defined by a
Blockly-generated Lua program instead of custom firmware (see the
updated kvida meta-repo vision). Removes the west/NCS/Zephyr scaffold
and replaces it with:

- A pinned ESP-IDF v6.0.2 Docker build environment (Espressif's
  official image already bundles the toolchain, unlike NCS/west).
- A layered component structure (drivers -> sensors -> profiles ->
  lua_runtime -> transport) matching the new architecture principles,
  with per-component READMEs describing responsibilities.
- An A/B OTA + LittleFS partition table and a minimal main.cpp.

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

docker/Dockerfile

@@ -1,21 +1,13 @@
 # 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.
+# Unlike the previous NCS/Zephyr setup, Espressif's official image already
+# bakes in the full ESP-IDF toolchain and the SDK itself for the pinned
+# version, so there is no separate multi-GB "fetch SDK into a volume" step
+# here -- just pin the image tag.
 #
-# 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
+# NOTE: verify this tag still exists before relying on it -- it could not
+# be checked against the live registry while writing this Dockerfile. If
+# the exact patch tag "v6.0.2" isn't published, fall back to "release-v6.0".
+FROM espressif/idf:v6.0.2
 
-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.
+WORKDIR /project