Harden BLE host link and expose latency tools in the dashboard.

Add BLE RTT/stream tests and live tick median in the UI, fix concurrent WebSocket writes and late BATTERY replies, and skip 2M PHY updates that assert under ESP-NOW coexistence.

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

main/ble_host.c

@@ -140,15 +140,13 @@ static void ble_request_fast_conn_params(uint16_t handle) {
 static void ble_optimize_link(uint16_t handle) {
   int rc;
 
+  /*
+   * Do NOT request 2M PHY here. With ESP-NOW/WiFi coexistence the controller
+   * can assert in llc_phy_upd (e.g. "BLE assert llc_phy_upd.c …") and the
+   * host link dies — no further responses. Stay on default 1M.
+   */
   ble_request_fast_conn_params(handle);
 
-  rc = ble_gap_set_prefered_le_phy(handle, BLE_GAP_LE_PHY_2M_MASK,
-                                   BLE_GAP_LE_PHY_2M_MASK,
-                                   BLE_GAP_LE_PHY_CODED_ANY);
-  if (rc != 0) {
-    ESP_LOGW(TAG, "2M PHY request failed: %d", rc);
-  }
-
   rc = ble_gap_set_data_len(handle, 251, 2120);
   if (rc != 0) {
     ESP_LOGW(TAG, "data len request failed: %d", rc);