fix: правильные координаты text selection — window→overlay-local конвертация

Root cause: overlay Canvas рисует в локальных координатах, но LayoutInfo
возвращает позицию в window coordinates. Разница = position status bar,
toolbar, и parent padding → highlight смещался вниз.

Фикс:
- onGloballyPositioned на overlay Box → знаем overlayWindowX/Y
- Canvas: offsetX/Y = info.windowX - overlayWindowX (window→local)
- getCharOffsetFromCoords: overlay-local → text-local через ту же delta
- Handle positions теперь в overlay-local координатах → drag работает

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/rosetta/messenger/ui/chats/components/TextSelectionHelper.kt

@@ -19,6 +19,7 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
@@ -34,6 +35,8 @@ import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.layout.onGloballyPositioned
+import androidx.compose.ui.layout.positionInWindow
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.text.font.FontWeight
@@ -77,6 +80,10 @@ class TextSelectionHelper {
     var endHandleX by mutableFloatStateOf(0f)
     var endHandleY by mutableFloatStateOf(0f)
 
+    // Overlay position in window — set by TextSelectionOverlay
+    var overlayWindowX = 0f
+    var overlayWindowY = 0f
+
     val isInSelectionMode: Boolean get() = isActive && selectionStart >= 0 && selectionEnd > selectionStart
 
     fun startSelection(
@@ -199,13 +206,14 @@ class TextSelectionHelper {
         magnifier = null
     }
 
-    fun getCharOffsetFromCoords(x: Int, y: Int): Int {
+    fun getCharOffsetFromCoords(overlayLocalX: Int, overlayLocalY: Int): Int {
         val info = layoutInfo ?: return -1
-        val localX = x - info.windowX
-        val localY = y - info.windowY
+        // overlay-local → text-local: subtract text position relative to overlay
+        val textLocalX = overlayLocalX - (info.windowX - overlayWindowX)
+        val textLocalY = overlayLocalY - (info.windowY - overlayWindowY)
         val layout = info.layout
-        val line = layout.getLineForVertical(localY.coerceIn(0, layout.height))
-        val hx = localX.toFloat().coerceIn(layout.getLineLeft(line), layout.getLineRight(line))
+        val line = layout.getLineForVertical(textLocalY.toInt().coerceIn(0, layout.height))
+        val hx = textLocalX.toFloat().coerceIn(layout.getLineLeft(line), layout.getLineRight(line))
         return layout.getOffsetForHorizontal(line, hx)
     }
 
@@ -324,7 +332,15 @@ fun TextSelectionOverlay(
     val handleInsetPx = with(density) { HandleInset.toPx() }
     val highlightCornerPx = with(density) { HighlightCorner.toPx() }
 
-    Box(modifier = modifier.fillMaxSize()) {
+    Box(
+        modifier = modifier
+            .fillMaxSize()
+            .onGloballyPositioned { coords ->
+                val pos = coords.positionInWindow()
+                helper.overlayWindowX = pos.x
+                helper.overlayWindowY = pos.y
+            }
+    ) {
         FloatingToolbarPopup(helper = helper)
         Canvas(
             modifier = Modifier
@@ -387,6 +403,10 @@ fun TextSelectionOverlay(
             val layout = info.layout
             val text = info.text
 
+            // Convert window coords to overlay-local coords
+            val offsetX = info.windowX - helper.overlayWindowX
+            val offsetY = info.windowY - helper.overlayWindowY
+
             val startOffset = helper.selectionStart.coerceIn(0, text.length)
             val endOffset = helper.selectionEnd.coerceIn(0, text.length)
             if (startOffset >= endOffset) return@Canvas
@@ -395,17 +415,17 @@ fun TextSelectionOverlay(
             val endLine = layout.getLineForOffset(endOffset)
 
             for (line in startLine..endLine) {
-                val lineTop = layout.getLineTop(line).toFloat() + info.windowY
-                val lineBottom = layout.getLineBottom(line).toFloat() + info.windowY
+                val lineTop = layout.getLineTop(line).toFloat() + offsetY
+                val lineBottom = layout.getLineBottom(line).toFloat() + offsetY
                 val left = if (line == startLine) {
-                    layout.getPrimaryHorizontal(startOffset) + info.windowX
+                    layout.getPrimaryHorizontal(startOffset) + offsetX
                 } else {
-                    layout.getLineLeft(line) + info.windowX
+                    layout.getLineLeft(line) + offsetX
                 }
                 val right = if (line == endLine) {
-                    layout.getPrimaryHorizontal(endOffset) + info.windowX
+                    layout.getPrimaryHorizontal(endOffset) + offsetX
                 } else {
-                    layout.getLineRight(line) + info.windowX
+                    layout.getLineRight(line) + offsetX
                 }
                 drawRoundRect(
                     color = HighlightColor,
@@ -415,10 +435,10 @@ fun TextSelectionOverlay(
                 )
             }
 
-            val startHx = layout.getPrimaryHorizontal(startOffset) + info.windowX
-            val startHy = layout.getLineBottom(startLine).toFloat() + info.windowY
-            val endHx = layout.getPrimaryHorizontal(endOffset) + info.windowX
-            val endHy = layout.getLineBottom(endLine).toFloat() + info.windowY
+            val startHx = layout.getPrimaryHorizontal(startOffset) + offsetX
+            val startHy = layout.getLineBottom(startLine).toFloat() + offsetY
+            val endHx = layout.getPrimaryHorizontal(endOffset) + offsetX
+            val endHy = layout.getLineBottom(endLine).toFloat() + offsetY
 
             helper.startHandleX = startHx
             helper.startHandleY = startHy