fix: embed firmware version from version.txt, log at boot (#354)

- Add version.txt (0.6.0) read by CMakeLists.txt so
  esp_app_get_description()->version matches the release tag
- Log firmware version on boot: "v0.6.0 — Node ID: X"
- Remove stale Kconfig help text (said default 2.0, actual is 15.0)

Fixes the version mismatch reported in #354 where flashing v0.5.3
binaries showed v0.4.3 because PROJECT_VER was never set.

Co-Authored-By: claude-flow <ruv@ruv.net>

firmware/esp32-csi-node/CMakeLists.txt

@@ -4,5 +4,10 @@ cmake_minimum_required(VERSION 3.16)
 
 set(EXTRA_COMPONENT_DIRS "")
 
+# Read firmware version from version.txt so esp_app_get_description()->version
+# matches the release tag.  Fixes issue #354 (version mismatch after flashing).
+file(STRINGS "${CMAKE_CURRENT_LIST_DIR}/version.txt" PROJECT_VER LIMIT_COUNT 1)
+string(STRIP "${PROJECT_VER}" PROJECT_VER)
+
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
-project(esp32-csi-node)
+project(esp32-csi-node VERSION ${PROJECT_VER})

firmware/esp32-csi-node/main/Kconfig.projbuild

@@ -76,7 +76,6 @@ menu "Edge Intelligence (ADR-039)"
             Raise to reduce false positives in high-traffic environments.
             Normal walking produces accelerations of 2-5 rad/s².
             Stored as integer; divided by 1000 at runtime.
-            Default 2000 = 2.0 rad/s^2.
 
     config EDGE_POWER_DUTY
         int "Power duty cycle percentage"

firmware/esp32-csi-node/main/main.c

@@ -16,6 +16,7 @@
 #include "esp_event.h"
 #include "esp_log.h"
 #include "nvs_flash.h"
+#include "esp_app_desc.h"
 #include "sdkconfig.h"
 
 #include "csi_collector.h"
@@ -137,7 +138,9 @@ void app_main(void)
     /* Load runtime config (NVS overrides Kconfig defaults) */
     nvs_config_load(&g_nvs_config);
 
-    ESP_LOGI(TAG, "ESP32-S3 CSI Node (ADR-018) — Node ID: %d", g_nvs_config.node_id);
+    const esp_app_desc_t *app_desc = esp_app_get_description();
+    ESP_LOGI(TAG, "ESP32-S3 CSI Node (ADR-018) — v%s — Node ID: %d",
+             app_desc->version, g_nvs_config.node_id);
 
     /* Initialize WiFi STA (skip entirely under QEMU mock — no RF hardware) */
 #ifndef CONFIG_CSI_MOCK_SKIP_WIFI_CONNECT

firmware/esp32-csi-node/version.txt

@@ -0,0 +1 @@
+0.6.0