feat: 底图bg1.png+开关灯合并按键+默认IP更新

- 添加 bg1.png 作为底层背景图，视频未播放时透出
- PlayerView 仅在视频播放中时渲染，避免黑色 SurfaceView 遮挡底图
- 开关灯合并为前灯/后灯两个按键，依据 LED 回报状态显示琥珀色/暗色
- 默认 IP 改为 10.21.41.1，RTSP 地址改为 rtsp://10.21.41.1:8554/video1

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

AGENTS.md

@@ -191,12 +191,12 @@ val y = power / 100.0 * sin(angle)   // 水平分量
 - [x] 摇杆尺寸增大：左右摇杆从 140dp 增大到 180dp，提升操控精度
 - [x] 视频缩放模式：`VideoResizeMode` 枚举（FIT/ZOOM/FILL），设置界面新增"视频缩放模式"下拉选项，持久化保存，实时生效
 - [x] 状态机修复：趴下状态下允许切换站立状态（机器人站立后自动进入 RL 控制，无需 App 下发）
+- [x] UI 布局：增加 bg1.png 作为底图，无视频流时显示（视频流播放时覆盖底图）
+- [x] UI 布局：开关灯合并为前灯/后灯两个按键，通过颜色（琥珀色=开/暗色=关）表示置位状态，配合机器人回报状态同步
 
 ### 待办
 
-- [ ] UI 布局：增加 logo 图作为底图，无视频流时显示底图
 - [ ] UI 布局：header 部分虽已避开状态栏，但底色与屏幕顶端视觉不吸附，需优化视觉传达效果
 - [ ] UI 布局：功能按钮均布在四周，充分利用屏幕空间，优化单手操作体验
-- [ ] UI 布局：开关灯合并为一个按键，通过图标/颜色表示置位状态，需配合机器人回报状态同步
 - [ ] 状态栏：增加 ICMP 延迟测量显示，显示当前 WiFi 强度和延迟 ms
 - [ ] 视频进一步延迟优化：探索更激进的低延迟策略（如降低帧率、缩小分辨率、调整 ExoPlayer 缓冲策略等）

app/src/main/java/com/example/m20_gamepad/data/AppSettings.kt

@@ -28,9 +28,9 @@ data class AppSettings(
     val videoResizeMode: VideoResizeMode = VideoResizeMode.ZOOM
 ) {
     companion object {
-        const val DEFAULT_ROBOT_HOST = "10.21.31.103"
+        const val DEFAULT_ROBOT_HOST = "10.21.41.1"
         const val DEFAULT_ROBOT_PORT = 30000
-        const val DEFAULT_RTSP_URL = "rtsp://10.21.31.103:554/stream"
+        const val DEFAULT_RTSP_URL = "rtsp://10.21.41.1:8554/video1"
 
         /** RTSP 端口范围校验 */
         fun isValidPort(port: Int): Boolean = port in 1..65535

app/src/main/java/com/example/m20_gamepad/ui/MainScreen.kt

@@ -1,5 +1,6 @@
 package com.example.m20_gamepad.ui
 
+import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -40,6 +41,8 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
@@ -49,9 +52,11 @@ import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
 import com.erz.joysticklibrary.Joystick
 import com.erz.joysticklibrary.JoystickType
+import com.example.m20_gamepad.R
 import com.example.m20_gamepad.data.SettingsRepository
 import com.example.m20_gamepad.network.ProtocolClient
 import com.example.m20_gamepad.network.models.ControlCommands
+import com.example.m20_gamepad.network.models.LedStatus
 import com.example.m20_gamepad.ui.components.StatusPanel
 import com.example.m20_gamepad.video.RtspVideoPlayer
 
@@ -83,6 +88,7 @@ fun MainScreen(
     val motionStatus by viewModel.motionStatus.collectAsStateWithLifecycle()
     val deviceTemperature by viewModel.deviceTemperature.collectAsStateWithLifecycle()
     val batteryStatus by viewModel.batteryStatus.collectAsStateWithLifecycle()
+    val ledStatus by viewModel.ledStatus.collectAsStateWithLifecycle()
     val lastUpdate by viewModel.lastUpdate.collectAsStateWithLifecycle()
     val actionFeedback by viewModel.actionFeedback.collectAsStateWithLifecycle()
 
@@ -99,6 +105,14 @@ fun MainScreen(
     }
 
     Box(modifier = Modifier.fillMaxSize()) {
+        // ---- 底图层（无视频流时显示） ----
+        Image(
+            painter = painterResource(id = R.drawable.bg1),
+            contentDescription = null,
+            contentScale = ContentScale.FillBounds,
+            modifier = Modifier.fillMaxSize()
+        )
+
         // ---- 视频背景层 ----
         RtspVideoPlayer(
             url = settings.rtspUrl,
@@ -123,6 +137,7 @@ fun MainScreen(
             viewModel = viewModel,
             connectionState = connectionState,
             motionState = motionState,
+            ledStatus = ledStatus,
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .windowInsetsPadding(WindowInsets.navigationBars)
@@ -245,6 +260,7 @@ private fun BottomControls(
     viewModel: MainViewModel,
     connectionState: ProtocolClient.State,
     motionState: Int,
+    ledStatus: LedStatus?,
     modifier: Modifier = Modifier
 ) {
     Row(
@@ -269,7 +285,8 @@ private fun BottomControls(
         ControlButtons(
             viewModel = viewModel,
             connectionState = connectionState,
-            motionState = motionState
+            motionState = motionState,
+            ledStatus = ledStatus
         )
 
         // 右摇杆（Yaw 旋转）
@@ -289,7 +306,8 @@ private fun BottomControls(
 private fun ControlButtons(
     viewModel: MainViewModel,
     connectionState: ProtocolClient.State,
-    motionState: Int
+    motionState: Int,
+    ledStatus: LedStatus?
 ) {
     val connected = connectionState == ProtocolClient.State.CONNECTED
     val isRlControl = motionState == ControlCommands.MOTION_RL_CONTROL
@@ -383,13 +401,23 @@ private fun ControlButtons(
 
             // 照明
             SectionLabel("照明")
+            val frontOn = ledStatus?.front == 1
+            val backOn = ledStatus?.back == 1
             Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
-                MiniButton("前灯开") { viewModel.sendLightControl(1, 0) }
+                LightToggleButton(
-                MiniButton("前灯关") { viewModel.sendLightControl(0, 0) }
+                    text = "前灯",
+                    isOn = frontOn,
+                    enabled = connected
+                ) {
+                    viewModel.sendLightControl(if (frontOn) 0 else 1, ledStatus?.back ?: 0)
+                }
+                LightToggleButton(
+                    text = "后灯",
+                    isOn = backOn,
+                    enabled = connected
+                ) {
+                    viewModel.sendLightControl(ledStatus?.front ?: 0, if (backOn) 0 else 1)
                 }
-            Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
-                MiniButton("后灯开") { viewModel.sendLightControl(0, 1) }
-                MiniButton("后灯关") { viewModel.sendLightControl(0, 0) }
             }
             Spacer(Modifier.height(4.dp))
 
@@ -451,6 +479,30 @@ private fun MiniButton(text: String, enabled: Boolean = true, onClick: () -> Uni
     }
 }
 
+@Composable
+private fun LightToggleButton(
+    text: String,
+    isOn: Boolean,
+    enabled: Boolean = true,
+    onClick: () -> Unit
+) {
+    Button(
+        onClick = onClick,
+        enabled = enabled,
+        colors = ButtonDefaults.buttonColors(
+            containerColor = if (isOn) Color(0xCCFFC107) else Color(0x66333333),
+            disabledContainerColor = Color(0x33222222)
+        ),
+        modifier = Modifier.width(110.dp)
+    ) {
+        Text(
+            "$text ${if (isOn) "开" else "关"}",
+            color = if (enabled) OverlayText else Color(0x88FFFFFF),
+            fontWeight = FontWeight.Medium
+        )
+    }
+}
+
 @Composable
 private fun SectionLabel(text: String) {
     Text(

app/src/main/java/com/example/m20_gamepad/ui/MainViewModel.kt

@@ -9,6 +9,7 @@ import com.example.m20_gamepad.network.models.BatteryStatus
 import com.example.m20_gamepad.network.models.ControlCommands
 import com.example.m20_gamepad.network.models.DeviceTemperature
 import com.example.m20_gamepad.network.models.ErrorInfo
+import com.example.m20_gamepad.network.models.LedStatus
 import com.example.m20_gamepad.network.models.MotionStatus
 import com.example.m20_gamepad.network.models.StatusReport
 import com.example.m20_gamepad.service.JoystickController
@@ -70,6 +71,9 @@ class MainViewModel(
     private val _batteryStatus = MutableStateFlow<BatteryStatus?>(null)
     val batteryStatus: StateFlow<BatteryStatus?> = _batteryStatus.asStateFlow()
 
+    private val _ledStatus = MutableStateFlow<LedStatus?>(null)
+    val ledStatus: StateFlow<LedStatus?> = _ledStatus.asStateFlow()
+
     private val _lastUpdate = MutableStateFlow<String?>(null)
     val lastUpdate: StateFlow<String?> = _lastUpdate.asStateFlow()
 
@@ -153,6 +157,7 @@ class MainViewModel(
         _motionStatus.value = null
         _deviceTemperature.value = null
         _batteryStatus.value = null
+        _ledStatus.value = null
         _lastUpdate.value = null
     }
 
@@ -165,6 +170,7 @@ class MainViewModel(
         report.motionStatus?.let { _motionStatus.value = it }
         report.deviceTemperature?.let { _deviceTemperature.value = it }
         report.batteryStatus?.let { _batteryStatus.value = it }
+        report.led?.let { _ledStatus.value = it }
         // 通用响应错误提示
         report.errorCode?.let { code ->
             if (code != 0) {

app/src/main/java/com/example/m20_gamepad/video/RtspVideoPlayer.kt

@@ -131,6 +131,8 @@ fun RtspVideoPlayer(
     }
 
     Box(modifier = modifier) {
+        // 仅在视频播放中时渲染 PlayerView，否则透出底层背景
+        if (state is RtspState.Playing) {
             AndroidView(
                 modifier = Modifier.fillMaxSize(),
                 factory = { ctx ->
@@ -138,15 +140,15 @@ fun RtspVideoPlayer(
                         useController = false
                         this.resizeMode = resizeMode.toMedia3ResizeMode()
                         this.player = player
-                    setShutterBackgroundColor(android.graphics.Color.BLACK)
+                        setShutterBackgroundColor(android.graphics.Color.TRANSPARENT)
                     }
                 },
-            // player 引用变化时（codec 重建）更新 PlayerView
                 update = { view ->
                     view.player = player
                     view.resizeMode = resizeMode.toMedia3ResizeMode()
                 }
             )
+        }
 
         // 连接中 / 错误时的提示覆盖层
         when (val s = state) {