feat: 添加 MyTermuxActivity 菜单及工具栏功能

- MainActivity 添加 MyTermuxActivity 菜单项
- 配置 MyTermuxActivity 注册到 AndroidManifest.xml
- 添加 Toolbar 布局并初始化工具栏
- 设置一级标题应用名称、二级标题活动名称
- 添加返回按钮导航逻辑

修改文件：MainActivity.java, MyTermuxActivity.java, activity_my_termux.xml, toolbar_main.xml, strings.xml, AndroidManifest.xml, gradlew

winboll/src/main/res/layout/activity_my_termux.xml

@@ -1,9 +1,24 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout
+<FrameLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
-    android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
-    
-</LinearLayout>
+
+    <androidx.appcompat.widget.Toolbar
+        android:id="@+id/toolbar"
+        android:layout_width="match_parent"
+        android:layout_height="?attr/actionBarSize"
+        android:background="?attr/colorPrimary"
+        app:title="@string/app_name"
+        app:subtitle="@string/my_termux_activity"
+        app:titleTextColor="@android:color/white"
+        app:subtitleTextColor="@android:color/white"/>
+
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_gravity="bottom"
+        android:layout_weight="1"/>
+
+</FrameLayout>

winboll/src/main/res/menu/toolbar_main.xml

@@ -5,6 +5,9 @@
         android:id="@+id/item_home"
         android:title="HOME"/>
 	<item
+        android:id="@+id/item_mytermux"
+        android:title="MyTermuxActivity"/>
+	<item
         android:id="@+id/item_settings"
         android:title="Settings"/>
 	<item

winboll/src/main/res/values/strings.xml

@@ -11,4 +11,5 @@
     <string name="cn2_switch_disabled">金抖云 X</string>
     <string name="tileservice_name">WinBoLL</string>
     <string name="toolbar_icon_description">WinBoLL APP</string>
+    <string name="my_termux_activity">MyTermuxActivity</string>
 </resources>