v0.7.1: rename C core header to victronble_core.h (fixes #2)

src/ held both VictronBLE.h and victronble.h. On case-insensitive
filesystems (Windows, macOS) extracting the library ZIP overwrote one
with the other and the Arduino build failed.

The core header is now victronble_core.h in include/ and src/, and every
include is updated. include/victronble.h stays as a deprecated forwarder
so 0.7.0 Zephyr and host code still builds; it is never in src/.

check_version.sh now fails if two tracked paths differ only in case.

library.json

@@ -1,6 +1,6 @@
 {
   "name": "victronble",
-  "version": "0.7.0",
+  "version": "0.7.1",
   "description": "Portable Arduino library for reading Victron Energy device data via Bluetooth Low Energy (BLE) advertisements. Runs on ESP32, ESP32-S3, ESP32-C3 and nRF52 (nRF52840, nRF52832). Supports SmartSolar MPPT, SmartShunt, BMV, MultiPlus, Orion, Blue Smart AC chargers and other Victron devices. No external crypto dependency. Also ships a Zephyr module (CONFIG_VICTRONBLE) and a dependency-free pure C99 core usable on any platform.",
   "keywords": "victron, ble, zephyr, bluetooth, solar, mppt, battery, smartshunt, smartsolar, bmv, inverter, multiplus, esp32, esp32-s3, esp32-c3, nrf52, nrf52840, nrf52832, xiao, iot, energy, monitoring",
   "repository": {