Add Lua runtime: chip temp -> LED color -> HA, verified live

Sandboxed Lua state (espressif/lua v5.5.0, base/table/string/math only,
no io/os/package/debug) exposes a kvida API table (chip_temperature,
set_led, publish) to a compiled-in default script that reads chip
temperature, maps it to an LED color, and publishes the reading to
Home Assistant. Generalizes transport's publish_chip_temperature()
into publish_value(name, value), the first real use of AGENTS.md's
semantic publish API. Requires -DLUA_32BITS globally since this
toolchain's long long support isn't visible to Lua's default build.

Verified on real ESP32-C6 hardware: no crashes/errors across multiple
serial monitor windows, LED changes color, chip_temperature sensor
appears in Home Assistant via MQTT Discovery.

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

main/CMakeLists.txt

@@ -1,5 +1,5 @@
-idf_component_register(
-    SRCS "main.cpp"
-    INCLUDE_DIRS "."
-    REQUIRES drivers sensors profiles transport lua_runtime esp_timer
-)
+idf_component_register(
+    SRCS "main.cpp"
+    INCLUDE_DIRS "."
+    REQUIRES drivers transport lua_runtime esp_timer
+)