feat: 添加Atguigu键盘板支持和IP5306电源管理驱动

添加了两个新的键盘板支持：
- atguigu_keyboard_dongle (基于nrf52833)
- atguigu_mini_keyboard (基于nrf52840)

同时添加了完整的IP5306电源管理芯片驱动，包括：
- 支持充电状态检测
- 提供软硬件保活脉冲功能
- 硬件后端利用nRF的RTC+GPIOTE+GPPI实现低功耗保活
- 软件后端作为备用方案

modules/ip5306/dts/bindings/power/injoinic,ip5306.yaml

@@ -0,0 +1,33 @@
+title: Injoinic IP5306 PMIC
+
+description: |
+  Injoinic IP5306 power management IC accessed over I2C.
+  This binding exposes two status bits and an optional KEY pin keepalive
+  pulse output.
+
+compatible: "injoinic,ip5306"
+
+include: i2c-device.yaml
+
+properties:
+  keepalive-gpios:
+    type: phandle-array
+    description: |
+      GPIO connected to KEY pin. The driver sends periodic pulses on this pin
+      to keep boost output alive.
+
+  keepalive-pulse-ms:
+    type: int
+    default: 100
+    description: Pulse width in milliseconds for each keepalive pulse.
+
+  keepalive-interval-ms:
+    type: int
+    default: 20000
+    description: Interval in milliseconds between keepalive pulses.
+
+  keepalive-offload:
+    type: boolean
+    description: |
+      Prefer hardware keepalive offload backend when available on this SoC.
+      If not set, driver always uses software keepalive backend.