fix(tooltip): cancel pending delay on exit and fix popup positioning

- Cancel pending hover delay job when pointer exits to prevent tooltip
  from appearing after cursor leaves
- Use PopupPositionProvider to position tooltip above anchor instead of
  overlapping it (centers horizontally, maintains 4dp gap)
- Replace coroutineScope+launch with rememberCoroutineScope for proper
  job lifecycle management

Author: kdroidFilter

macosui/src/commonMain/kotlin/io/github/kdroidfilter/nucleus/ui/apple/macos/components/Tooltip.kt

@@ -10,26 +10,30 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
 import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.shadow
 import androidx.compose.ui.graphics.graphicsLayer
-import androidx.compose.ui.input.pointer.PointerEventPass
 import androidx.compose.ui.input.pointer.PointerEventType
 import androidx.compose.ui.input.pointer.PointerType
 import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.IntOffset
+import androidx.compose.ui.unit.IntRect
+import androidx.compose.ui.unit.IntSize
+import androidx.compose.ui.unit.LayoutDirection
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.window.Popup
+import androidx.compose.ui.window.PopupPositionProvider
 import androidx.compose.ui.window.PopupProperties
 import io.github.kdroidfilter.nucleus.ui.apple.macos.components.Text
 import io.github.kdroidfilter.nucleus.ui.apple.macos.theme.MacosTheme
-import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 
@@ -61,39 +65,57 @@ fun Tooltip(
     val colors = MacosTheme.colorScheme
     val typography = MacosTheme.typography
     val shapes = MacosTheme.shapes
+    val density = LocalDensity.current
+    val scope = rememberCoroutineScope()
 
     var showTooltip by remember { mutableStateOf(false) }
+    var hoverJob: Job? by remember { mutableStateOf(null) }
 
-    // Fade animation
     val alpha by animateFloatAsState(
         targetValue = if (showTooltip) 1f else 0f,
         animationSpec = tween(durationMillis = 100),
         label = "tooltipAlpha",
     )
 
-    // Tooltip colors: inverted from current theme
     val tooltipBackground = colors.inverseSurface
-
     val tooltipTextColor = colors.inverseOnSurface
 
+    val gapPx = with(density) { 4.dp.roundToPx() }
+    val positionProvider = remember(gapPx) {
+        object : PopupPositionProvider {
+            override fun calculatePosition(
+                anchorBounds: IntRect,
+                windowSize: IntSize,
+                layoutDirection: LayoutDirection,
+                popupContentSize: IntSize,
+            ): IntOffset = IntOffset(
+                x = (anchorBounds.left + (anchorBounds.width - popupContentSize.width) / 2)
+                    .coerceIn(0, (windowSize.width - popupContentSize.width).coerceAtLeast(0)),
+                y = anchorBounds.top - popupContentSize.height - gapPx,
+            )
+        }
+    }
+
     Box(
         modifier = modifier
             .pointerInput(Unit) {
-                coroutineScope {
-                    awaitPointerEventScope {
-                        val pass = PointerEventPass.Main
-                        while (true) {
-                            val event = awaitPointerEvent(pass)
-                            val inputType = event.changes.firstOrNull()?.type
-                            if (inputType == PointerType.Mouse) {
-                                when (event.type) {
-                                    PointerEventType.Enter -> launch {
+                awaitPointerEventScope {
+                    while (true) {
+                        val event = awaitPointerEvent()
+                        val inputType = event.changes.firstOrNull()?.type
+                        if (inputType == PointerType.Mouse) {
+                            when (event.type) {
+                                PointerEventType.Enter -> {
+                                    hoverJob?.cancel()
+                                    hoverJob = scope.launch {
                                         delay(delayMillis)
                                         showTooltip = true
                                     }
-                                    PointerEventType.Exit -> {
-                                        showTooltip = false
-                                    }
+                                }
+                                PointerEventType.Exit -> {
+                                    hoverJob?.cancel()
+                                    hoverJob = null
+                                    showTooltip = false
                                 }
                             }
                         }
@@ -105,11 +127,8 @@ fun Tooltip(
 
         if (showTooltip || alpha > 0f) {
             Popup(
-                alignment = Alignment.TopCenter,
-                offset = IntOffset(0, -8),
-                properties = PopupProperties(
-                    focusable = false,
-                ),
+                popupPositionProvider = positionProvider,
+                properties = PopupProperties(focusable = false),
             ) {
                 Box(
                     modifier = Modifier