feat: add SwooshMotion shared animation specs

app/src/main/java/com/swoosh/microblog/ui/animation/SwooshMotion.kt

@@ -0,0 +1,43 @@
+package com.swoosh.microblog.ui.animation
+
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.FiniteAnimationSpec
+import androidx.compose.animation.core.spring
+import androidx.compose.animation.core.tween
+
+object SwooshMotion {
+
+    // Expressive bounce — FAB entrance, chips, badges. One visible overshoot.
+    fun <T> bouncy(): FiniteAnimationSpec<T> = spring(
+        dampingRatio = 0.65f,
+        stiffness = 400f
+    )
+
+    // Fast snap-back — press feedback, button taps. Settles in ~150ms.
+    fun <T> bouncyQuick(): FiniteAnimationSpec<T> = spring(
+        dampingRatio = 0.7f,
+        stiffness = 1000f
+    )
+
+    // Controlled spring — expand/collapse, dialogs.
+    fun <T> snappy(): FiniteAnimationSpec<T> = spring(
+        dampingRatio = 0.7f,
+        stiffness = 800f
+    )
+
+    // Soft entrance — cards, content reveal.
+    fun <T> gentle(): FiniteAnimationSpec<T> = spring(
+        dampingRatio = 0.8f,
+        stiffness = 300f
+    )
+
+    // Quick tween — fade, color transitions.
+    fun <T> quick(): FiniteAnimationSpec<T> = tween(
+        durationMillis = 200,
+        easing = FastOutSlowInEasing
+    )
+
+    // Stagger delays
+    const val StaggerDelayMs = 50L
+    const val RevealDelayMs = 80L
+}