fix: 编译错误 — 显式类型标注、补充缺失 import

- AirDisplayManager: SAM conversion 推断失败，改用显式 object 表达式
- MainActivity: 补充 android.util.Log import
- MainScreen: 补充 androidx.compose.ui.graphics.Color import

app/src/main/java/com/qwenpaw/miracast/AirDisplayManager.kt

@@ -92,10 +92,12 @@ class AirDisplayManager(private val context: Context) {
 
         // 协议管理器
         protocol = ProtocolManager(wifiDirect)
-        wifiDirect.setWfdStatusListener { status ->
-            Log.i(TAG, "WFD IE: $status")
-            protocol.onWfdStatusChanged(status)
-        }
+        wifiDirect.setWfdStatusListener(object : WiFiDirectManager.WfdStatusListener {
+            override fun onWfdStatusChanged(status: WiFiDirectManager.WfdStatus) {
+                Log.i(TAG, "WFD IE: $status")
+                protocol.onWfdStatusChanged(status)
+            }
+        })
 
         // 媒体渲染器
         renderer = MediaRenderer()

app/src/main/java/com/qwenpaw/miracast/ui/MainActivity.kt

@@ -8,6 +8,7 @@ import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
 import android.os.IBinder
+import android.util.Log
 import android.view.SurfaceView
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent

app/src/main/java/com/qwenpaw/miracast/ui/MainScreen.kt

@@ -14,6 +14,7 @@ import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp