espressif/_bleio: restore CIRCUITPY_VERBOSE_BLE discovery prints

Restore the verbose prints dropped when discovery object construction
moved off the NimBLE host task, and add matching error prints to all
three discovery callbacks for consistency (only the descriptor callback
had one before). The object prints now live in _build_characteristic()
and _build_descriptor(), which run on the VM task. Also print the step
status in _check_discovery_status(), which covers the timeout and
ring-full errors that never pass through a callback.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: dhalbert

ports/espressif/common-hal/_bleio/Connection.c

@@ -193,6 +193,10 @@ static void _set_discovery_step_status(int status) {
 }
 
 static void _check_discovery_status(int status) {
+    #if CIRCUITPY_VERBOSE_BLE
+    mp_printf(&mp_plat_print, "discovery step status: %d\n", status);
+    #endif
+
     if (status == BLE_HS_EDONE) {
         return;
     }
@@ -268,6 +272,11 @@ static int _discovered_service_cb(uint16_t conn_handle,
     const struct ble_gatt_svc *svc,
     void *arg) {
     if (error->status != 0) {
+        #if CIRCUITPY_VERBOSE_BLE
+        mp_printf(&mp_plat_print, "_discovered_service_cb error->status: %d, handle: %d\n",
+            error->status, error->att_handle);
+        #endif
+
         // BLE_HS_EDONE or some error has occurred.
         _set_discovery_step_status(error->status);
         return 0;
@@ -285,6 +294,11 @@ static int _discovered_characteristic_cb(uint16_t conn_handle,
     const struct ble_gatt_chr *chr,
     void *arg) {
     if (error->status != 0) {
+        #if CIRCUITPY_VERBOSE_BLE
+        mp_printf(&mp_plat_print, "_discovered_characteristic_cb error->status: %d, handle: %d\n",
+            error->status, error->att_handle);
+        #endif
+
         // BLE_HS_EDONE or some error has occurred.
         _set_discovery_step_status(error->status);
         return 0;
@@ -303,6 +317,11 @@ static int _discovered_descriptor_cb(uint16_t conn_handle,
     const struct ble_gatt_dsc *dsc,
     void *arg) {
     if (error->status != 0) {
+        #if CIRCUITPY_VERBOSE_BLE
+        mp_printf(&mp_plat_print, "_discovered_descriptor_cb error->status: %d, handle: %d\n",
+            error->status, error->att_handle);
+        #endif
+
         // BLE_HS_EDONE or some error has occurred.
         _set_discovery_step_status(error->status);
         return 0;
@@ -412,6 +431,10 @@ static void _build_characteristic(void *ctx, const void *record) {
     // Set def_handle directly since it is only used in discovery.
     characteristic->def_handle = chr->def_handle;
 
+    #if CIRCUITPY_VERBOSE_BLE
+    mp_printf(&mp_plat_print, "_build_characteristic: char handle: %d\n", characteristic->handle);
+    #endif
+
     mp_obj_list_append(MP_OBJ_FROM_PTR(service->characteristic_list),
         MP_OBJ_FROM_PTR(characteristic));
 }
@@ -449,6 +472,11 @@ static void _build_descriptor(void *ctx, const void *record) {
         GATT_MAX_DATA_LENGTH, false, mp_const_empty_bytes);
     descriptor->handle = dsc->handle;
 
+    #if CIRCUITPY_VERBOSE_BLE
+    mp_printf(&mp_plat_print, "_build_descriptor: char handle: %d, desc handle: %d, uuid type: %d, u16 value: 0x%x\n",
+        characteristic->handle, descriptor->handle, dsc->uuid.u.type, dsc->uuid.u16.value);
+    #endif
+
     mp_obj_list_append(MP_OBJ_FROM_PTR(characteristic->descriptor_list),
         MP_OBJ_FROM_PTR(descriptor));
 }