fix: переписать SlideToCancel 1:1 с Telegram — chevron arrow, пульсация, entry animation

Telegram-exact SlideTextView:
- Chevron arrow: Canvas-drawn path 4×5dp, stroke 1.6dp, round caps (не текст ◀)
- Пульсация: ±6dp ТОЛЬКО при slideProgress > 0.8, скорость 12dp/s (3dp/250ms)
- Frame-based animation через LaunchedEffect (не infiniteTransition)
- Entry: slide in from right (translationX 20dp→0, 200ms) + fade in
- Текст: "Slide to cancel" 15sp normal weight (было 13sp medium)
- Цвет: #8E8E93 (Telegram key_chat_recordTime)
- Translation: finger × 0.3 damping + pulse offset × slideProgress
- Alpha: slideProgress × entryAlpha (плавно появляется и исчезает при свайпе)

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

app/src/main/java/com/rosetta/messenger/ui/chats/input/ChatDetailInput.kt

@@ -569,6 +569,19 @@ private fun LockIcon(
     }
 }
 
+/**
+ * Telegram-exact SlideToCancel.
+ *
+ * Layout: [chevron arrow]  "Slide to cancel"
+ *
+ * - Arrow is a Canvas-drawn chevron (4×5dp, stroke 1.6dp, round caps)
+ * - Arrow oscillates ±6dp ONLY when slideProgress > 0.8 at 12dp/s
+ * - Text alpha = slideProgress (fades in with drag, 0 = invisible at rest)
+ * - Translation follows finger × 0.3 damping
+ * - Entry: slides in from right (translationX 20dp→0) with fade
+ *
+ * Reference: ChatActivityEnterView.SlideTextView (lines 13083-13357)
+ */
 @Composable
 private fun SlideToCancel(
     slideDx: Float,
@@ -576,46 +589,119 @@ private fun SlideToCancel(
     isDarkTheme: Boolean,
     modifier: Modifier = Modifier
 ) {
-    val slideRatio = ((-slideDx) / cancelThresholdPx).coerceIn(0f, 1f)
+    // slideProgress: 1.0 = at rest, decreases as finger drags left toward cancel
-    val textAlpha = if (slideRatio > 0.7f) 1f - ((slideRatio - 0.7f) / 0.3f) else 1f
+    val slideProgress = 1f - ((-slideDx) / cancelThresholdPx).coerceIn(0f, 1f)
 
-    // Fix #5: Arrow pulsation ±6dp when slideRatio > 0.8, else ±3dp
+    val density = LocalDensity.current
-    val arrowAmplitude = if (slideRatio > 0.8f) -6f else -3f
+
-    val arrowPulse = rememberInfiniteTransition(label = "slide_cancel_arrow")
+    // Pre-compute px values for use in LaunchedEffect
-    val arrowOffset by arrowPulse.animateFloat(
+    val maxOffsetPx = with(density) { 6.dp.toPx() }
-        initialValue = 0f,
+    val speedPxPerMs = with(density) { (3f / 250f).dp.toPx() } // 12dp/s
-        targetValue = arrowAmplitude,
+
-        animationSpec = infiniteRepeatable(
+    // Telegram: arrow oscillates ±6dp only when slideProgress > 0.8
-            animation = tween(durationMillis = 500, easing = LinearEasing),
+    var xOffset by remember { mutableFloatStateOf(0f) }
-            repeatMode = RepeatMode.Reverse
+    var moveForward by remember { mutableStateOf(true) }
-        ),
+
-        label = "slide_cancel_arrow_offset"
+    LaunchedEffect(slideProgress > 0.8f) {
+        if (slideProgress <= 0.8f) {
+            xOffset = 0f
+            moveForward = true
+            return@LaunchedEffect
+        }
+        var lastTime = System.nanoTime()
+        while (true) {
+            delay(16) // ~60fps
+            val now = System.nanoTime()
+            val dtMs = (now - lastTime) / 1_000_000f
+            lastTime = now
+
+            val step = speedPxPerMs * dtMs
+            if (moveForward) {
+                xOffset += step
+                if (xOffset > maxOffsetPx) {
+                    xOffset = maxOffsetPx
+                    moveForward = false
+                }
+            } else {
+                xOffset -= step
+                if (xOffset < -maxOffsetPx) {
+                    xOffset = -maxOffsetPx
+                    moveForward = true
+                }
+            }
+        }
+    }
+
+    // Colors — Telegram: key_chat_recordTime (gray), key_glass_defaultIcon (arrow)
+    val textColor = if (isDarkTheme) Color(0xFF8E8E93) else Color(0xFF8E8E93)
+    val arrowColor = if (isDarkTheme) Color(0xFFAAAAAA) else Color(0xFF8E8E93)
+
+    // Entry animation: slide in from right
+    var entered by remember { mutableStateOf(false) }
+    LaunchedEffect(Unit) {
+        entered = true
+    }
+    val entryTranslation by animateFloatAsState(
+        targetValue = if (entered) 0f else with(density) { 20.dp.toPx() },
+        animationSpec = tween(durationMillis = 200, easing = FastOutSlowInEasing),
+        label = "slide_cancel_entry"
+    )
+    val entryAlpha by animateFloatAsState(
+        targetValue = if (entered) 1f else 0f,
+        animationSpec = tween(durationMillis = 200),
+        label = "slide_cancel_entry_alpha"
     )
 
-    val textColor = if (isDarkTheme) Color.White.copy(alpha = 0.6f) else Color.Black.copy(alpha = 0.4f)
-
-    // Fix #6: damping 0.3 (Telegram-style)
     Row(
         modifier = modifier
             .graphicsLayer {
-                translationX = slideDx * 0.3f
+                // Telegram: text follows finger × damping + entry slide + pulse offset
-                alpha = textAlpha
+                translationX = slideDx * 0.3f + entryTranslation +
+                    xOffset * slideProgress
+                alpha = slideProgress * entryAlpha
             },
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = Arrangement.Center
     ) {
-        Text(
+        // Chevron arrow — Canvas-drawn, NOT text character
-            text = "◀",
+        // Telegram: 4dp × 5dp chevron, stroke 1.6dp, round caps
-            color = textColor,
+        Canvas(
-            fontSize = 13.sp,
+            modifier = Modifier
-            modifier = Modifier.graphicsLayer { translationX = arrowOffset }
+                .size(width = 10.dp, height = 14.dp)
-        )
+                .graphicsLayer {
+                    translationX = xOffset * slideProgress
+                }
+        ) {
+            val midY = size.height / 2f
+            val arrowW = 4.dp.toPx()
+            val arrowH = 5.dp.toPx()
+            val strokeW = 1.6f.dp.toPx()
+            val startX = (size.width - arrowW) / 2f
+
+            drawLine(
+                color = arrowColor,
+                start = Offset(startX + arrowW, midY - arrowH),
+                end = Offset(startX, midY),
+                strokeWidth = strokeW,
+                cap = androidx.compose.ui.graphics.StrokeCap.Round
+            )
+            drawLine(
+                color = arrowColor,
+                start = Offset(startX, midY),
+                end = Offset(startX + arrowW, midY + arrowH),
+                strokeWidth = strokeW,
+                cap = androidx.compose.ui.graphics.StrokeCap.Round
+            )
+        }
+
         Spacer(modifier = Modifier.width(4.dp))
+
+        // "Slide to cancel" text — Telegram: 15sp, normal weight
         Text(
-            text = "Slide to Cancel",
+            text = "Slide to cancel",
             color = textColor,
-            fontSize = 13.sp,
+            fontSize = 15.sp,
-            fontWeight = FontWeight.Medium,
+            fontWeight = FontWeight.Normal,
             maxLines = 1
         )
     }