Reveal swipe actions from trailing (right) edge (#34)

Flip SwipeableItemWithActions so users drag the row right-to-left to
reveal action buttons, with the buttons sitting on the trailing (right)
edge instead of the leading (left) edge. Matches the iOS app's
swipeActions(edge: .trailing) and the platform-conventional
swipe-to-reveal gesture.

- Actions Row aligned to Alignment.CenterEnd of the wrapping Box
- Drag offset coerced to [-contextMenuWidth, 0f]
- Revealed anchor flipped to -contextMenuWidth; half-way fling threshold
  checks <= -contextMenuWidth / 2f

Public API (isRevealed, actions, onExpanded, onCollapsed, content,
modifier) is unchanged, so both call sites pick up the new direction
with no edits:
- ShopDetailView — Complete / Idle actions on item-tag rows
- ItemTagListView — Delete action on item-tag rows

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

Author: dadachi

app/src/main/kotlin/com/nativeapptemplate/nativeapptemplatefree/ui/common/SwipeableItemWithActions.kt

@@ -46,7 +46,7 @@ fun SwipeableItemWithActions(
 
   LaunchedEffect(key1 = isRevealed, contextMenuWidth) {
     if (isRevealed) {
-      offset.animateTo(contextMenuWidth)
+      offset.animateTo(-contextMenuWidth)
     } else {
       offset.animateTo(0f)
     }
@@ -59,6 +59,7 @@ fun SwipeableItemWithActions(
   ) {
     Row(
       modifier = Modifier
+        .align(Alignment.CenterEnd)
         .onSizeChanged {
           contextMenuWidth = it.width.toFloat()
         },
@@ -75,15 +76,15 @@ fun SwipeableItemWithActions(
             onHorizontalDrag = { _, dragAmount ->
               scope.launch {
                 val newOffset = (offset.value + dragAmount)
-                  .coerceIn(0f, contextMenuWidth)
+                  .coerceIn(-contextMenuWidth, 0f)
                 offset.snapTo(newOffset)
               }
             },
             onDragEnd = {
               when {
-                offset.value >= contextMenuWidth / 2f -> {
+                offset.value <= -contextMenuWidth / 2f -> {
                   scope.launch {
-                    offset.animateTo(contextMenuWidth)
+                    offset.animateTo(-contextMenuWidth)
                     onExpanded()
                   }
                 }