feat: 配置Android签名与APK后缀大写

新增release.keystore并在build.gradle中配置签名信息，发布包启用签名。统一Android APK文件后缀为大写.APK，调整CI流程相关路径匹配。

android/app/build.gradle

@@ -27,11 +27,21 @@ android {
         }
     }
 
+    signingConfigs {
+        release {
+            storeFile file('release.keystore')
+            storePassword 'ogame123'
+            keyAlias 'ogame'
+            keyPassword 'ogame123'
+        }
+    }
+
     buildTypes {
         release {
             minifyEnabled true
             shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+            signingConfig signingConfigs.release
         }
     }
 
@@ -46,7 +56,7 @@ android {
             def abi = output.getFilter(com.android.build.OutputFile.ABI)
             if (abi != null) {
                 output.versionCodeOverride = abiVersionCode[abi] * 1000 + defaultConfig.versionCode
-                output.outputFileName = "OGame-${defaultConfig.versionName}-${abi}.apk"
+                output.outputFileName = "OGame-${defaultConfig.versionName}-${abi}.APK"
             }
         }
     }