feat(l2): Arduino-ESP32 3.3.12 / IDF 5.5 env, NimBLE and new I2S driver ports, large UI buffers in PSRAM

- New env Wio_Tracker_L2_companion_solo_lvgl_v3 on pioarduino 55.03.312-1;
  the 2.0.17 env stays until the new one passes the hardware checklist
- SerialBLEInterface: NimBLE variant (PIN pairing through encrypted,
  authenticated characteristic properties; setAccessPermissions is a no-op)
- buzzer: i2s_std driver on IDF 5 (legacy driver kept for 2.0.17)
- ESPNOWRadio: IDF 5 callback signatures
- ui-lvgl: psramBuf() for trail drawing, tile cache, map marks, list rows,
  keyboard maps and message metadata; internal heap back to 2.0.17 level

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

solo/wio-tracker-l2/platformio.ini

@@ -75,3 +75,20 @@ lib_deps =
   HTTPClient
   WiFiClientSecure
   Preferences
+
+; The same firmware on Arduino-ESP32 3.x (ESP-IDF 5.5, pioarduino). Runs beside
+; the 2.0.17 env above until it passes docs/development/l2-hardware-checklist.md
+; (roadmap stage 2), then replaces it.
+[env:Wio_Tracker_L2_companion_solo_lvgl_v3]
+extends = env:Wio_Tracker_L2_companion_solo_lvgl
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.312-1/platform-espressif32.zip
+lib_deps =
+  ${Wio_Tracker_L2.lib_deps}
+  densaugeo/base64 @ ~1.4.0
+  lvgl/lvgl @ 9.2.2
+  SD_MMC
+  FS
+  WiFi
+  HTTPClient
+  NetworkClientSecure ; 3.x name of WiFiClientSecure (the header is still there)
+  Preferences