style: 电池显示优化

- 百分比文字放大 15f→18f，颜色跟随电池状态
- 充电时加 ⚡ 前缀（如 ⚡73%），一眼可见充电状态
- 颜色分级更清晰：>60%绿 / 21-60%白 / 11-20%橙 / ≤10%红
- 低电量时电池壳也变红，整体醒目
- 统一 getBatteryColor() 逻辑复用

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/xiaoqu/watch/ui/widget/StatusBarView.kt

@@ -79,13 +79,23 @@ class StatusBarView @JvmOverloads constructor(
         }
     }
 
+    /** 获取电池状态颜色（统一逻辑） */
+    private fun getBatteryColor(): Int = when {
+        isCharging -> colorGreen
+        batteryLevel <= 10 -> colorRed
+        batteryLevel <= 20 -> colorOrange
+        batteryLevel <= 60 -> colorWhite
+        else -> colorGreen
+    }
+
     /** 绘制电量百分比文字（电池图标左侧） */
     private fun drawBatteryText(canvas: Canvas, rightEdge: Float, centerY: Float) {
         if (batteryLevel < 0) return  // 未获取时不显示
-        val text = "${batteryLevel}%"
+        // 充电时显示 ⚡ 前缀
+        val text = if (isCharging) "⚡${batteryLevel}%" else "${batteryLevel}%"
         paint.style = Paint.Style.FILL
-        paint.color = 0x99FFFFFF.toInt() // 白色 60% 透明度
+        paint.color = getBatteryColor()
-        paint.textSize = 15f
+        paint.textSize = 18f
         paint.textAlign = Paint.Align.RIGHT
         val metrics = paint.fontMetrics
         val baselineY = centerY - (metrics.ascent + metrics.descent) / 2
@@ -93,28 +103,23 @@ class StatusBarView @JvmOverloads constructor(
         paint.textAlign = Paint.Align.LEFT
     }
 
-    /** 绘制电池图标（壳 + 填充条 + 凸起 + 充电闪电） */
+    /** 绘制电池图标（壳 + 填充条 + 凸起） */
     private fun drawBattery(canvas: Canvas, startX: Float, centerY: Float) {
         val shellW = 28f
         val shellH = 13f
         val shellTop = centerY - shellH / 2
         val cornerR = 3.5f
 
-        // 电池壳边框
+        // 电池壳边框（颜色跟随状态）
         paint.style = Paint.Style.STROKE
         paint.strokeWidth = 1.5f
-        paint.color = colorBorder
+        paint.color = if (batteryLevel <= 10 && !isCharging) colorRed else colorBorder
         val shellRect = RectF(startX, shellTop, startX + shellW, shellTop + shellH)
         canvas.drawRoundRect(shellRect, cornerR, cornerR, paint)
 
         // 电池填充条
         paint.style = Paint.Style.FILL
-        paint.color = when {
+        paint.color = getBatteryColor()
-            isCharging -> colorGreen
-            batteryLevel <= 10 -> colorRed
-            batteryLevel <= 20 -> colorOrange
-            else -> colorGreen
-        }
         val fillPadding = 2.5f
         val fillMaxW = shellW - fillPadding * 2
         val fillW = fillMaxW * batteryLevel.coerceAtLeast(0) / 100f
@@ -126,10 +131,8 @@ class StatusBarView @JvmOverloads constructor(
         )
         canvas.drawRoundRect(fillRect, 2f, 2f, paint)
 
-        // 充电状态通过填充条颜色区分（绿色=充电中，已在上方 when 处理）
-
         // 电池凸起（右侧小矩形）
-        paint.color = colorBorder
+        paint.color = if (batteryLevel <= 10 && !isCharging) colorRed else colorBorder
         val nubW = 2.5f
         val nubH = 6f
         val nubRect = RectF(