Add BLE host transport selectable via DIP8 alongside UART.

Master can speak the same framed protobuf protocol over NimBLE or UART; goTool gains -ble, ble-rtt, and ble-stream timing checks for ESP-NOW coexistence.

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

main/ble_stream.h

@@ -0,0 +1,18 @@
+#ifndef BLE_STREAM_H
+#define BLE_STREAM_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/** Clamp and store BLE push period (8–16 ms). */
+void ble_stream_set_period_ms(uint32_t period_ms);
+
+uint32_t ble_stream_period_ms(void);
+
+/**
+ * Re-evaluate whether the BLE push task should run (host_ble + any accel
+ * stream enabled). Safe to call from accel-stream handlers.
+ */
+void ble_stream_update(void);
+
+#endif