Fix collapse drag not tracking finger — use dynamic dragRange based on actual height change

The fixed DRAG_RANGE_DP=200dp caused the collapse progress to advance faster
than the visual height change, making the calendar feel like it "outruns" the
finger. Now dragRangePx is computed as (weeks-1)×rowHeight, matching the
actual visual height delta during collapse so finger movement maps 1:1 to
visual change.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

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

@@ -16,7 +16,6 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.pointer.pointerInput
-import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.unit.dp
 import plus.rua.project.CalendarViewModel
 
@@ -24,16 +23,16 @@ import plus.rua.project.CalendarViewModel
  * 底部卡片，折叠状态下支持垂直拖拽触发折叠动画。
  *
  * @param viewModel 日历 ViewModel，用于读取折叠状态和驱动拖拽
+ * @param dragRangePx 拖拽手势映射范围（像素），progress 从 0→1 对应手指移动此距离。
+ *   应设为折叠时日历实际高度变化量 (weeks-1)×rowHeight，使拖拽跟手。
  * @param modifier 外部布局修饰符
  */
 @Composable
 fun BottomCard(
     viewModel: CalendarViewModel,
+    dragRangePx: Float,
     modifier: Modifier = Modifier
 ) {
-    val density = LocalDensity.current
-    val dragRange = with(density) { DRAG_RANGE_DP.dp.toPx() }
-
     Surface(
         modifier = modifier
             .fillMaxWidth()
@@ -48,7 +47,7 @@ fun BottomCard(
                             viewModel.onExpandDragEnd()
                         }
                     ) { _, dragAmount ->
-                        val delta = -dragAmount / dragRange
+                        val delta = -dragAmount / dragRangePx
                         viewModel.onExpandDrag(delta)
                     }
                 } else {
@@ -61,7 +60,7 @@ fun BottomCard(
                             viewModel.onDragEnd()
                         }
                     ) { _, dragAmount ->
-                        val delta = -dragAmount / dragRange
+                        val delta = -dragAmount / dragRangePx
                         viewModel.onDrag(delta)
                     }
                 }
@@ -82,4 +81,4 @@ fun BottomCard(
             )
         }
     }
-}
+}

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

@@ -180,9 +180,18 @@ fun CalendarMonthView(
             }
         }
 
-        if (cardHeightPx > 0) {
+        // 拖拽范围 = 折叠时日历实际高度变化量 (weeks-1)×rowHeight，使手指移动与视觉变化 1:1 对应
+    val dragRangeMinPx = with(density) { DRAG_RANGE_MIN_DP.dp.toPx() }
+    val dragRangePx = if (effectiveRowHeightPx > 0) {
+        maxOf((effectiveWeeks - 1) * effectiveRowHeightPx.toFloat(), dragRangeMinPx)
+    } else {
+        dragRangeMinPx
+    }
+
+    if (cardHeightPx > 0) {
             BottomCard(
                 viewModel = viewModel,
+                dragRangePx = dragRangePx,
                 modifier = Modifier
                     .fillMaxWidth()
                     .height(with(density) { cardHeightPx.toDp() })

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

@@ -21,8 +21,8 @@ const val ROW_PADDING_DP = 6
 /** 日历网格水平 padding (dp) */
 const val HORIZONTAL_PADDING_DP = 16
 
-/** BottomCard 拖拽手势范围 (dp) */
-const val DRAG_RANGE_DP = 200
+/** BottomCard 拖拽手势范围最小值 (dp)，防止行数少时 dragRange 过小 */
+const val DRAG_RANGE_MIN_DP = 100
 
 /** 日历与 BottomCard 之间的间距 (dp)：展开时 */
 const val CARD_GAP_EXPANDED_DP = 24