fix: 恢复折叠动画 Phase 2 下方行偏移，移除 showWeekPager 切换

- 恢复 CalendarMonthPage 中 isBelow 行的 `- phase2 * belowRowsHeight`
  （2592a5f 误删导致展开时下方行原地淡入而非滑出）
- 移除 CalendarMonthView 的 showWeekPager + AnimatedContent 切换
  （完全折叠后下拉拖拽时只显示 WeekPager 单周，上下空白）
- 回退到始终显示 CalendarPager，由 CalendarMonthPage 处理折叠动画
- 添加详细动画调试日志（Page/WeekRow/View 三层）

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

core/src/main/kotlin/plus/rua/project/ui/CalendarMonthPage.kt

@@ -106,6 +106,17 @@ fun CalendarMonthPage(
     val anchorIndex = remember(year, month, selectedDate) {
         weeks.indexOfFirst { week -> week.any { it.date == selectedDate } }
     }
+
+    // 全局动画参数日志（每次重组）
+    val pageFrameNs = System.nanoTime()
+    Log.d(
+        TAG_CMP,
+        "Page[$year-$month]: anchorIndex=$anchorIndex weeksSize=${weeks.size} " +
+            "phase1End=${if (anchorIndex > 0 && weeks.size > 1) anchorIndex.toFloat() / (weeks.size - 1) else 0f} " +
+            "effectiveWeeks=$effectiveWeeks rowHeightPx=$rowHeightPx " +
+            "collapseProgress=$collapseProgress frameNs=$pageFrameNs"
+    )
+
     val totalHeightDp = if (rowHeightPx > 0) {
         val h = rowHeightPx.toFloat()
         val totalPx = h * (1 + (effectiveWeeks - 1) * (1f - collapseProgress))
@@ -188,7 +199,7 @@ private fun WeekRow(
             !hasAnchor -> weekIndex * h - collapseProgress * weeksSize * h
             isAnchor -> anchorIndex * h * (1f - phase1)
             isAbove -> weekIndex * h - phase1 * anchorIndex * h
-            isBelow -> weekIndex * h - phase1 * anchorIndex * h
+            isBelow -> weekIndex * h - phase1 * anchorIndex * h - phase2 * belowRowsHeight
             else -> weekIndex * h
         }
     } else 0f
@@ -201,9 +212,17 @@ private fun WeekRow(
         else -> 1f
     }
 
-    if (isAnchor || isBelow) {
-        Log.d(TAG_CMP, "WeekRow[$weekIndex]: isAnchor=$isAnchor isAbove=$isAbove isBelow=$isBelow phase1=$phase1 phase2=$phase2 yOffsetPx=$yOffsetPx rowAlpha=$rowAlpha collapseProgress=$collapseProgress")
-    }
+    val frameTimeNs = System.nanoTime()
+    Log.d(
+        TAG_CMP,
+        "WeekRow[$weekIndex]: " +
+            "isAnchor=$isAnchor isAbove=$isAbove isBelow=$isBelow " +
+            "phase1=$phase1 phase2=$phase2 phase1End=$phase1End " +
+            "belowRowsHeight=$belowRowsHeight rowHeightPx=$rowHeightPx " +
+            "yOffsetPx=$yOffsetPx rowAlpha=$rowAlpha " +
+            "collapseProgress=$collapseProgress " +
+            "frameNs=$frameTimeNs"
+    )
 
     if (rowAlpha > 0.01f) {
         Row(

core/src/main/kotlin/plus/rua/project/ui/CalendarMonthView.kt

@@ -48,6 +48,7 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableIntStateOf
@@ -69,7 +70,6 @@ import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.unit.dp
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
-import kotlinx.datetime.DatePeriod
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.TimeZone
 import kotlinx.datetime.number
@@ -82,6 +82,7 @@ import plus.rua.project.composeTraceEndSection
 import kotlin.math.abs
 import kotlin.time.Clock
 import androidx.lifecycle.viewmodel.compose.viewModel
+import android.util.Log
 
 /**
  * 日历主界面，包含月/周视图切换、折叠动画和年视图共享元素转场。
@@ -118,6 +119,9 @@ fun CalendarMonthView(
         animationSpec = spring(stiffness = Spring.StiffnessMedium),
         label = "collapseProgress"
     )
+    SideEffect {
+        Log.d("CalendarExpandAnim", "View: target=$collapseProgress animated=$animatedCollapseProgress isCollapsed=$isCollapsed")
+    }
 
     val density = LocalDensity.current
     val coroutineScope = rememberCoroutineScope()
@@ -238,7 +242,6 @@ fun CalendarMonthView(
                                 CalendarPagerArea(
                                     selectedDate = selectedDate,
                                     today = today,
-                                    isCollapsed = isCollapsed,
                                     collapseProgress = animatedCollapseProgress,
                                     showLegalHoliday = showLegalHoliday,
                                     rowHeightPx = rowHeightPx,
@@ -463,7 +466,6 @@ private fun MenuIcon(color: Color, modifier: Modifier = Modifier) {
 private fun CalendarPagerArea(
     selectedDate: LocalDate,
     today: LocalDate,
-    isCollapsed: Boolean,
     collapseProgress: Float,
     showLegalHoliday: Boolean,
     rowHeightPx: Int,
@@ -520,66 +522,20 @@ private fun CalendarPagerArea(
         modifier
     }
 
-    // 延迟切换：等折叠 spring 动画完全稳定后再切到 WeekPager，避免视觉跳跃
-    var showWeekPager by remember { mutableStateOf(false) }
-
-    LaunchedEffect(isCollapsed, collapseProgress) {
-        if (isCollapsed && collapseProgress >= 0.999f) {
-            delay(50)
-            showWeekPager = true
-        } else if (!isCollapsed) {
-            showWeekPager = false
-        }
-    }
-
-    AnimatedContent(
-        targetState = showWeekPager,
-        transitionSpec = { fadeIn(tween(80)) togetherWith fadeOut(tween(80)) },
-        label = "pager_switch",
+    CalendarPager(
+        selectedDate = selectedDate,
+        today = today,
+        onDateClick = onDateClick,
+        onMonthChanged = onMonthChanged,
+        collapseProgress = collapseProgress,
+        rowHeightPx = rowHeightPx,
+        effectiveWeeks = effectiveWeeks,
+        shiftKindAt = shiftKindAt,
+        showLegalHoliday = showLegalHoliday,
+        onRowHeightMeasured = onRowHeightMeasured,
+        pagerState = pagerState,
         modifier = pagerModifier
-    ) { useWeekPager ->
-        if (useWeekPager) {
-            WeekPager(
-                selectedDate = selectedDate,
-                today = today,
-                onDateClick = onDateClick,
-                onWeekChanged = { weekMonday ->
-                    val weekSunday = weekMonday.plus(DatePeriod(days = 6))
-                    val date = when {
-                        today in weekMonday..weekSunday -> today
-                        weekMonday.month != weekSunday.month -> {
-                            if (weekMonday < selectedDate) {
-                                @Suppress("DEPRECATION")
-                                LocalDate(weekSunday.year, weekSunday.month.number, 1)
-                            } else {
-                                weekMonday
-                            }
-                        }
-                        else -> weekMonday
-                    }
-                    onDateClick(date)
-                },
-                shiftKindAt = shiftKindAt,
-                showLegalHoliday = showLegalHoliday,
-                modifier = Modifier
-            )
-        } else {
-            CalendarPager(
-                selectedDate = selectedDate,
-                today = today,
-                onDateClick = onDateClick,
-                onMonthChanged = onMonthChanged,
-                collapseProgress = collapseProgress,
-                rowHeightPx = rowHeightPx,
-                effectiveWeeks = effectiveWeeks,
-                shiftKindAt = shiftKindAt,
-                showLegalHoliday = showLegalHoliday,
-                onRowHeightMeasured = onRowHeightMeasured,
-                pagerState = pagerState,
-                modifier = Modifier
-            )
-        }
-    }
+    )
 }
 
 @Composable