revert(month): put the morph back on the calendar's own motion specs (#53)

The trigger was what felt slow, and firing on the threshold instead of on
release already fixed that. Speeding up the animation on top of it was a
second change to the same complaint, and not one that was asked for — the
morph goes back to the shared calendar slide and fade specs, so it moves at
the same pace as every other transition in the app.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthMorph.kt

@@ -1,18 +1,13 @@
 package de.jeanlucmakiola.calendula.ui.month
 
 import androidx.compose.animation.AnimatedVisibilityScope
-import androidx.compose.animation.BoundsTransform
 import androidx.compose.animation.ExperimentalSharedTransitionApi
 import androidx.compose.animation.SharedTransitionScope
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
-import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
-import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.compositionLocalOf
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.geometry.Rect
 import kotlinx.datetime.LocalDate
 
 /**
@@ -61,22 +56,6 @@ internal class MonthMorphScope(
 
 internal val LocalMonthMorph = compositionLocalOf<MonthMorphScope?> { null }
 
-/**
- * How fast a tagged piece travels between its two homes.
- *
- * The *fast* spatial spec, not the default one the month/week/day page slide
- * uses. Paging is a spring under one whole page and wants room to settle; this is
- * a direct answer to a drag the user has already committed to, and at the default
- * pace the grid felt like it was catching up rather than responding. It is also
- * a hundred-odd pieces moving at once, where a long settle reads as lag.
- */
-@OptIn(ExperimentalSharedTransitionApi::class, ExperimentalMaterial3ExpressiveApi::class)
-@Composable
-internal fun rememberMorphBoundsTransform(): BoundsTransform {
-    val spec = MaterialTheme.motionScheme.fastSpatialSpec<Rect>()
-    return remember(spec) { BoundsTransform { _, _ -> spec } }
-}
-
 /**
  * Tag content that is *the same thing* on both sides — a background pill, a day
  * number — so it animates between its two positions and sizes.
@@ -89,7 +68,6 @@ internal fun Modifier.morphElement(key: MonthMorphKey): Modifier {
         this@morphElement.sharedElement(
             sharedContentState = rememberSharedContentState(key),
             animatedVisibilityScope = morph.visibility,
-            boundsTransform = rememberMorphBoundsTransform(),
         )
     }
 }
@@ -114,7 +92,6 @@ internal fun Modifier.morphBounds(key: MonthMorphKey): Modifier {
             animatedVisibilityScope = morph.visibility,
             enter = fadeIn(),
             exit = fadeOut(),
-            boundsTransform = rememberMorphBoundsTransform(),
             resizeMode = SharedTransitionScope.ResizeMode.RemeasureToBounds,
         )
     }

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthScreen.kt

@@ -47,7 +47,6 @@ import androidx.compose.material.icons.filled.Menu
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -909,7 +908,7 @@ private val MONTH_EXPAND_THRESHOLD = 48.dp
  * screen to explain why. [rememberSaveable] carries it across a rotation, which
  * is as long as it should live.
  */
-@OptIn(ExperimentalSharedTransitionApi::class, ExperimentalMaterial3ExpressiveApi::class)
+@OptIn(ExperimentalSharedTransitionApi::class)
 @Composable
 private fun SplitMonthContent(
     state: MonthUiState,
@@ -924,9 +923,7 @@ private fun SplitMonthContent(
     onEventClick: (EventInstance) -> Unit,
     onCreateEvent: (LocalDate) -> Unit,
 ) {
-    // The fast effects spec, matching the morph's fast spatial one — the page
+    val fadeSpec = rememberCalendarFadeSpec()
-    // slide's default pace made the swap trail behind a gesture already committed.
-    val fadeSpec = MaterialTheme.motionScheme.fastEffectsSpec<Float>()
     val reduceMotion = rememberReduceMotion()
     var expanded by rememberSaveable { mutableStateOf(false) }
     // Back collapses before it does anything else. Expanding replaces the whole