refactor: extract duplicate format functions to FormatUtils

- New: ui/components/FormatUtils.kt — formatAmount/formatResetInSec/formatResetForWidget/normalizeWindowLabel
- ServiceBalanceCards.kt: remove internal definitions, import from FormatUtils
- ServiceDetailScreen.kt: remove private formatResetInSec/formatAmount, import from FormatUtils
- OpenCodeGoWidgetProvider.kt: remove private normalizeWindowLabel, import from FormatUtils
  (formatReset kept — widget uses short d/h/m format, not Chinese)

app/src/main/java/com/rainy/token/ui/components/FormatUtils.kt

@@ -0,0 +1,47 @@
+package com.rainy.token.ui.components
+
+import java.util.Locale
+
+/**
+ * 共享格式化工具函数。
+ *
+ * 从 DashboardScreen / ServiceDetailScreen / WidgetProvider 提取，消除三处重复。
+ */
+
+/** 格式化金额：整数无小数点，带小数保留 2 位 */
+fun formatAmount(value: Double): String {
+    return if (value % 1.0 == 0.0) value.toInt().toString()
+    else String.format(Locale.US, "%.2f", value)
+}
+
+/** 格式化重置倒计时（秒 → "X 天 Y 小时" / "X 小时 Y 分" / "Y 分"），无效返回 "—" */
+fun formatResetInSec(sec: Long): String {
+    if (sec <= 0) return "—"
+    val days = sec / 86400
+    val hours = (sec % 86400) / 3600
+    val minutes = (sec % 3600) / 60
+    return when {
+        days > 0 -> "$days 天 $hours 小时"
+        hours > 0 -> "$hours 小时 $minutes 分"
+        else -> "$minutes 分"
+    }
+}
+
+/** Widget 版本：逻辑相同但空值返回空串（非 "—"），适配 RemoteViews 布局 */
+fun formatResetForWidget(sec: Long): String {
+    if (sec <= 0) return ""
+    val days = sec / 86400
+    val hours = (sec % 86400) / 3600
+    val minutes = (sec % 3600) / 60
+    return when {
+        days > 0 -> "$days 天 $hours 小时"
+        hours > 0 -> "$hours 小时 $minutes 分"
+        else -> "$minutes 分"
+    }
+}
+
+/** 标准化窗口标签：weekly → 每周，其他原样返回 */
+fun normalizeWindowLabel(label: String): String = when (label.lowercase()) {
+    "weekly" -> "每周"
+    else -> label
+}

app/src/main/java/com/rainy/token/ui/dashboard/ServiceBalanceCards.kt

@@ -24,6 +24,9 @@ import com.rainy.token.domain.model.ServiceBalance
 import com.rainy.token.domain.service.ServiceType
 import com.rainy.token.ui.components.StatusStyle
 import com.rainy.token.ui.components.StatusLevel
+import com.rainy.token.ui.components.formatAmount
+import com.rainy.token.ui.components.formatResetInSec
+import com.rainy.token.ui.components.normalizeWindowLabel
 import com.rainy.token.ui.theme.StrawberryPink
 import com.rainy.token.ui.theme.StatusOrange
 import com.rainy.token.ui.theme.inkMuted
@@ -353,11 +356,6 @@ internal fun OllamaUsageWindows(balance: ServiceBalance) {
 
 // ── Shared UI components ──
 
-internal fun normalizeWindowLabel(label: String): String = when (label.lowercase()) {
-    "weekly" -> "每周"
-    else -> label
-}
-
 @Composable
 internal fun CompactUsageRowEmpty(label: String, resetInSec: Long?) {
     Column {
@@ -452,18 +450,6 @@ internal fun CompactUsageRow(label: String, pct: Int, resetInSec: Long?) {
 
 // ── Dashboard utility functions ──
 
-internal fun formatResetInSec(sec: Long): String {
-    if (sec <= 0) return "—"
-    val days = sec / 86400
-    val hours = (sec % 86400) / 3600
-    val minutes = (sec % 3600) / 60
-    return when {
-        days > 0 -> "$days 天 $hours 小时"
-        hours > 0 -> "$hours 小时 $minutes 分"
-        else -> "$minutes 分"
-    }
-}
-
 internal fun DashboardCardUi.statusBadgeStyle(): StatusStyle = when {
     credentialState == CredentialStatus.State.NOT_CONFIGURED ->
         StatusStyle("未配置", StatusLevel.WARNING)
@@ -504,8 +490,3 @@ internal fun footerText(card: DashboardCardUi): String {
         else -> "$timeStr 更新"
     }
 }
-
-internal fun formatAmount(value: Double): String {
-    return if (value % 1.0 == 0.0) value.toInt().toString()
-    else String.format(Locale.US, "%.2f", value)
-}

app/src/main/java/com/rainy/token/ui/servicedetail/ServiceDetailScreen.kt

@@ -51,6 +51,8 @@ import com.rainy.token.ui.components.ServiceIcon
 import com.rainy.token.ui.components.StatusChip
 import com.rainy.token.ui.components.StatusLevel
 import com.rainy.token.ui.components.StatusStyle
+import com.rainy.token.ui.components.formatAmount
+import com.rainy.token.ui.components.formatResetInSec
 import com.rainy.token.ui.theme.inkMuted
 import com.rainy.token.ui.theme.StrawberryPink
 import java.text.SimpleDateFormat
@@ -388,18 +390,6 @@ private fun UsageWindowRow(label: String, pct: Int?, resetInSec: Long?) {
     }
 }
 
-private fun formatResetInSec(sec: Long): String {
-    if (sec <= 0) return "—"
-    val days = sec / 86400
-    val hours = (sec % 86400) / 3600
-    val minutes = (sec % 3600) / 60
-    return when {
-        days > 0 -> "$days 天 $hours 小时"
-        hours > 0 -> "$hours 小时 $minutes 分"
-        else -> "$minutes 分"
-    }
-}
-
 /**
  * Ollama Pro 专属：5h + 每周用量窗口卡。
  */
@@ -722,8 +712,3 @@ private fun formatTime(epochMillis: Long): String {
     val sdf = SimpleDateFormat("MM-dd HH:mm", Locale.getDefault())
     return sdf.format(Date(epochMillis))
 }
-
-private fun formatAmount(value: Double): String {
-    return if (value % 1.0 == 0.0) value.toInt().toString()
-    else String.format(Locale.US, "%.2f", value)
-}

app/src/main/java/com/rainy/token/ui/widget/OpenCodeGoWidgetProvider.kt

@@ -14,6 +14,7 @@ import com.rainy.token.R
 import com.rainy.token.data.cache.BalanceCache
 import com.rainy.token.data.cache.balanceCacheDataStore
 import com.rainy.token.domain.service.ServiceType
+import com.rainy.token.ui.components.normalizeWindowLabel
 import kotlinx.coroutines.runBlocking
 import java.text.SimpleDateFormat
 import java.util.Date
@@ -218,11 +219,6 @@ class OpenCodeGoWidgetProvider : AppWidgetProvider() {
         views.setTextViewText(R.id.row3_label, third)
     }
 
-    private fun normalizeWindowLabel(label: String): String = when (label.lowercase()) {
-        "weekly" -> "每周"
-        else -> label
-    }
-
     private fun populateRow(
         views: RemoteViews,
         pctViewId: Int,