style: 移除班次标签背景圆，清理未使用导入

DayCell 中右上角班次("班"/"休")标签去除 surface 背景圆，
文字直接浮在单元格上，视觉更轻量。同步清理
CalendarViewModel、AnimatedGif、BottomCard 的未使用导入，
并格式化 YearGridView 与 CalendarUtilsExtraTest。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shared/src/commonMain/kotlin/plus/rua/project/CalendarViewModel.kt

@@ -19,8 +19,6 @@ import kotlinx.datetime.minus
 import kotlinx.datetime.number
 import kotlinx.datetime.plus
 import kotlinx.datetime.todayIn
-import plus.rua.project.composeTraceBeginSection
-import plus.rua.project.composeTraceEndSection
 import plus.rua.project.ui.COLLAPSE_THRESHOLD
 import plus.rua.project.ui.FLING_VELOCITY_THRESHOLD_DP
 import kotlin.time.Clock

shared/src/commonMain/kotlin/plus/rua/project/ui/AnimatedGif.kt

@@ -1,9 +1,7 @@
 package plus.rua.project.ui
 
-import androidx.compose.foundation.layout.size
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.unit.dp
 import com.github.panpf.sketch.AsyncImage
 
 /**

shared/src/commonMain/kotlin/plus/rua/project/ui/BottomCard.kt

@@ -22,7 +22,6 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalDensity
-import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import kotlinx.datetime.LocalDate
@@ -52,6 +51,7 @@ fun BottomCard(
 ) {
     val density = LocalDensity.current
     val relativeDesc = relativeDayDescription(selectedDate, today)
+
     @Suppress("DEPRECATION") // monthNumber 无替代 API，kotlinx-datetime 尚未提供新接口
     val solarDesc = "${selectedDate.monthNumber}月${selectedDate.day}日"
     val lunarDesc = formatLunarDate(selectedDate)

shared/src/commonMain/kotlin/plus/rua/project/ui/DayCell.kt

@@ -5,7 +5,6 @@ import androidx.compose.animation.core.FastOutSlowInEasing
 import androidx.compose.animation.core.animateFloat
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.core.updateTransition
-import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.layout.Box
@@ -274,10 +273,8 @@ fun DayCell(
             }
             val shiftLabel = if (shiftKind == ShiftKind.WORK) "班" else "休"
             val shiftAlpha = if (isCurrentMonth) 1f else 0.38f
-            // 右上角(默认)沿用法定调休视觉:surface 背景 + 彩色文字;
+            // 右上角(默认)无背景,文字直接浮在单元格上;
             // 左上角(showLegalHoliday=true 时)用实心胶囊,与右上角法定调休区分。
-            val shiftBgColor =
-                if (showLegalHoliday) shiftAccentColor else MaterialTheme.colorScheme.surface
             val shiftFgColor = if (showLegalHoliday) shiftOnAccentColor else shiftAccentColor
             val shiftAlignment = if (showLegalHoliday) Alignment.TopStart else Alignment.TopEnd
             val shiftPadding = if (showLegalHoliday) {
@@ -295,7 +292,6 @@ fun DayCell(
                     .align(shiftAlignment)
                     .zIndex(1f)
                     .then(shiftPadding)
-                    .background(shiftBgColor.copy(alpha = shiftAlpha), CircleShape)
                     .padding(horizontal = 2.dp)
             )
         }
@@ -310,7 +306,6 @@ fun DayCell(
                     .align(Alignment.TopEnd)
                     .zIndex(1f)
                     .padding(top = 1.dp, end = 2.dp)
-                    .background(MaterialTheme.colorScheme.surface, CircleShape)
                     .padding(horizontal = 2.dp)
             )
         }

shared/src/commonMain/kotlin/plus/rua/project/ui/YearGridView.kt

@@ -112,7 +112,11 @@ fun YearGridView(
             listOf(
                 (month to true) to textMeasurer.measure(
                     text,
-                    TextStyle(fontSize = 10.sp, color = colors.titleSelected, fontWeight = FontWeight.Bold)
+                    TextStyle(
+                        fontSize = 10.sp,
+                        color = colors.titleSelected,
+                        fontWeight = FontWeight.Bold
+                    )
                 ),
                 (month to false) to textMeasurer.measure(
                     text,

shared/src/commonTest/kotlin/plus/rua/project/ui/CalendarUtilsExtraTest.kt

@@ -26,35 +26,50 @@ class CalendarUtilsExtraTest {
     fun calculateWeeksCountForPage_forwardOnePage_returnsNextMonthRows() {
         // From May 2026, +1 -> June 2026
         val today = LocalDate(2026, 5, 15)
-        assertEquals(calculateWeeksCount(2026, 6), calculateWeeksCountForPage(START_PAGE + 1, today))
+        assertEquals(
+            calculateWeeksCount(2026, 6),
+            calculateWeeksCountForPage(START_PAGE + 1, today)
+        )
     }
 
     @Test
     fun calculateWeeksCountForPage_backwardOnePage_returnsPreviousMonthRows() {
         // From May 2026, -1 -> April 2026
         val today = LocalDate(2026, 5, 15)
-        assertEquals(calculateWeeksCount(2026, 4), calculateWeeksCountForPage(START_PAGE - 1, today))
+        assertEquals(
+            calculateWeeksCount(2026, 4),
+            calculateWeeksCountForPage(START_PAGE - 1, today)
+        )
     }
 
     @Test
     fun calculateWeeksCountForPage_crossYearForward() {
         // From December 2026, +1 -> January 2027
         val today = LocalDate(2026, 12, 10)
-        assertEquals(calculateWeeksCount(2027, 1), calculateWeeksCountForPage(START_PAGE + 1, today))
+        assertEquals(
+            calculateWeeksCount(2027, 1),
+            calculateWeeksCountForPage(START_PAGE + 1, today)
+        )
     }
 
     @Test
     fun calculateWeeksCountForPage_crossYearBackward() {
         // From January 2026, -1 -> December 2025
         val today = LocalDate(2026, 1, 10)
-        assertEquals(calculateWeeksCount(2025, 12), calculateWeeksCountForPage(START_PAGE - 1, today))
+        assertEquals(
+            calculateWeeksCount(2025, 12),
+            calculateWeeksCountForPage(START_PAGE - 1, today)
+        )
     }
 
     @Test
     fun calculateWeeksCountForPage_twelvePagesForward_returnsSameMonthOfNextYear() {
         val today = LocalDate(2026, 5, 15)
         // +12 -> May 2027
-        assertEquals(calculateWeeksCount(2027, 5), calculateWeeksCountForPage(START_PAGE + 12, today))
+        assertEquals(
+            calculateWeeksCount(2027, 5),
+            calculateWeeksCountForPage(START_PAGE + 12, today)
+        )
     }
 
     // ---- relativeDayDescription ----