feat(calendar): convert toolbar to collapsed FAB next to InputBar

- CalendarToolbar is now collapsed by default as a FAB button
- FAB positioned right next to the QuickInputBar
- Toolbar panel opens above on click with smooth slide animation
- Reduced bottom padding since toolbar no longer takes full width
- DateStrip position adjusted to be closer to InputBar
- Updated localStorage logic (default is now collapsed)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/shared-splitscreen/src/components/SplitPaneContainer.svelte

@@ -81,7 +81,7 @@
 		width: 100%;
 		height: 100%;
 		min-height: 0;
-		overflow: hidden;
+		overflow: clip;
 		position: relative;
 	}
 
@@ -99,7 +99,7 @@
 		height: 100%;
 		min-width: 0;
 		min-height: 0;
-		overflow: hidden;
+		overflow: clip;
 	}
 
 	.side-panel {