zephyr/boards/nucleo_wb55rg: Enable BLE, I2C, SPI and add filesystem.

Bluetooth works well now on this board, so enable all supported features.

Also increase the MicroPython GC heap size to make use of the available
RAM.

Unfortunately the filesystem does not match the stm32 port's NUCLEO_WB55
configuration.  That's not possible to do because stm32 uses a 512 byte
flash erase size, while zephyr uses 4096 bytes.  But at least here in
zephyr there's now a sizable and usable filesystem.

Signed-off-by: Damien George <damien@micropython.org>

ports/zephyr/boards/nucleo_wb55rg.conf

@@ -1,5 +1,21 @@
 CONFIG_NETWORKING=n
+
+# Hardware features
+CONFIG_FLASH=y
+CONFIG_FLASH_MAP=y
+CONFIG_I2C=y
+CONFIG_SPI=y
+
+# Bluetooth
 CONFIG_BT=y
 CONFIG_BT_DEVICE_NAME_DYNAMIC=y
+CONFIG_BT_GATT_DYNAMIC_DB=y
 CONFIG_BT_PERIPHERAL=y
 CONFIG_BT_CENTRAL=y
+CONFIG_BT_GATT_CLIENT=y
+CONFIG_BT_L2CAP_TX_MTU=252
+CONFIG_BT_BUF_ACL_RX_SIZE=256
+CONFIG_BT_GATT_ENFORCE_SUBSCRIPTION=n
+
+# MicroPython config
+CONFIG_MICROPY_HEAP_SIZE=131072

ports/zephyr/boards/nucleo_wb55rg.overlay

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Damien P. George
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* Delete the defined partitions and create bigger one for storage. */
+/delete-node/ &slot1_partition;
+/delete-node/ &scratch_partition;
+/delete-node/ &storage_partition;
+&flash0 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		/* Storage slot: 424 KiB placed after slot0_partition. */
+		storage_partition: partition@70000 {
+			label = "storage";
+			reg = <0x00070000 DT_SIZE_K(424)>;
+		};
+	};
+};