Disables fill: forwards for spacer height animation

Removes the `fill: 'forwards'` property to ensure CSS `calc()` takes over the header spacer's height after the animation concludes.

src/managers/AllDayManager.ts

@@ -231,7 +231,7 @@ export class AllDayManager {
       })
     ];
 
-    // Add spacer animation if spacer exists
+    // Add spacer animation if spacer exists, but don't use fill: 'forwards'
     if (headerSpacer) {
       const root = document.documentElement;
       const currentSpacerHeight = parseInt(getComputedStyle(root).getPropertyValue('--header-height')) + currentHeight;
@@ -243,8 +243,8 @@ export class AllDayManager {
           { height: `${targetSpacerHeight}px` }
         ], {
           duration: 150,
-          easing: 'ease-out',
-          fill: 'forwards'
+          easing: 'ease-out'
+          // No fill: 'forwards' - let CSS calc() take over after animation
         })
       );
     }