Enable host OTA over BLE and harden ESP-NOW slave distribution.

Allow the same staged firmware upload path on BLE as UART, fix distribute stack/event-group crashes, and recover sticky slave OTA sessions instead of failing with err=4.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/docs/API_REST.md

@@ -138,7 +138,7 @@ POST /api/ble/scan
 
 Dashboard WebSocket state includes `host_connected`, `host_transport`, `host_endpoint` (aliases `uart_connected` / `serial_port` kept).
 
-**OTA** (`POST /api/ota`) returns **400** unless `transport==uart` and connected.
+**OTA** (`POST /api/ota`) returns **400** unless a host (UART or BLE) is connected.
 
 ### BLE latency tests (BLE host only)
 
@@ -400,14 +400,14 @@ go run . -port /dev/ttyUSB0 log-level -set -level 3
 
 Dashboard: Master card → dropdown **ESP Log-Level** with **Lesen** / **Setzen**.
 
-### OTA (master UART upload)
+### OTA (master host upload, UART or BLE)
 
 ```http
 POST /api/ota
 Content-Type: multipart/form-data
 ```
 
-Form field **`firmware`**: binary image, max **2 MiB**.
+Form field **`firmware`**: binary image, max **2 MiB**. Requires connected host (`transport` uart or ble). BLE needs ATT MTU ≥ 219 for 200 B chunks.
 
 ```json
 {"success": true, "bytes_written": 123456, "target_slot": 1}
@@ -415,7 +415,12 @@ Form field **`firmware`**: binary image, max **2 MiB**.
 
 Firmware distributes to slaves over ESP-NOW after `OTA_END`. Progress also appears on dashboard WebSocket as `ota_progress` messages.
 
-CLI equivalent: `go run . -port /dev/ttyUSB0 ota build/powerpod.bin`
+CLI equivalent:
+
+```bash
+go run . -port /dev/ttyUSB0 ota build/powerpod.bin
+go run . -ble ota build/powerpod.bin
+```
 
 ### LED ring and battery