fix: 电池内部数字改为黑色，避免和填充条颜色混淆

白字压绿底几乎看不见，改为黑色在任何填充色上都清晰

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

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

@@ -116,10 +116,11 @@ class StatusBarView @JvmOverloads constructor(
         canvas.drawRoundRect(fillRect, 2f, 2f, paint)
 
         // 电池内部文字：充电时显示 ⚡，否则显示百分比
+        // 深色文字确保在任何填充色上都清晰可读
         if (batteryLevel >= 0) {
             val text = if (isCharging) "⚡" else "${batteryLevel}"
             paint.style = Paint.Style.FILL
-            paint.color = 0xFFFFFFFF.toInt()
+            paint.color = 0xFF000000.toInt()
             paint.textSize = 11f
             paint.textAlign = Paint.Align.CENTER
             paint.typeface = android.graphics.Typeface.DEFAULT_BOLD