v0.7.0: pure C core + Zephyr module

- Extract all decode/decrypt into a dependency-free C99 core
 (include/victronble.h, src/victronble_core.c): victronble_decode(),
 is_product_adv/key_matches pre-filters, NAN sentinels, LE accessors.
- AES-128-CTR behind a hook: weak-symbol bundled tiny-AES default,
 runtime override (victronble_set_aes_ctr) for PSA/mbedTLS/hardware.
- Arduino VictronBLE class becomes a thin wrapper over the core
 (registry + nonce dedup + rate limit); public C++ API unchanged,
 NAN converted back to the legacy 0 convention.
- Host test vectors (tests/vectors): openssl-generated ciphertext,
 independent of the bundled AES; all five payload shapes + negatives.
- Zephyr module: zephyr/module.yml + Kconfig (CONFIG_VICTRONBLE) +
 observer backend (victronble_zephyr.{h,c}) — scan cb pre-filters and
 queues, dedicated decode thread, listener callbacks, slow passive
 scan defaults, stats counters. docs/ZEPHYR_PORT.md records the plan.
- library.properties: fix URL (gitea, not the nonexistent GitHub).

library.json

@@ -1,6 +1,6 @@
 {
   "name": "victronble",
-  "version": "0.6.1",
+  "version": "0.7.0",
   "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.",
   "keywords": "victron, ble, bluetooth, solar, mppt, battery, smartshunt, smartsolar, bmv, inverter, multiplus, esp32, esp32-s3, esp32-c3, nrf52, nrf52840, nrf52832, xiao, iot, energy, monitoring",
   "repository": {