Adds scroll synchronization for calendar view

Introduces ScrollManager to synchronize time axis and header scrolling

Improves user experience by keeping time axis and header aligned during scrolling
Enables dynamic vertical and horizontal scroll tracking for calendar components

wwwroot/css/calendar-v2.css

@@ -2,6 +2,8 @@
   --hour-height: 60px;
   --time-axis-width: 60px;
   --grid-columns: 5;
+  --day-start-hour: 0;
+  --day-end-hour: 24;
   --color-border: #e0e0e0;
   --color-surface: #fff;
   --color-text-secondary: #666;
@@ -68,6 +70,7 @@ swp-calendar-container {
   grid-template-columns: var(--time-axis-width) 1fr;
   grid-template-rows: auto 1fr;
   overflow: hidden;
+  height: 100%;
 }
 
 /* Time axis */
@@ -78,6 +81,7 @@ swp-time-axis {
   grid-template-rows: subgrid;
   border-right: 1px solid var(--color-border);
   background: var(--color-surface);
+  overflow: hidden;
 }
 
 swp-header-spacer {
@@ -85,8 +89,8 @@ swp-header-spacer {
 }
 
 swp-time-axis-content {
-  display: flex;
-  flex-direction: column;
+  display: grid;
+  grid-auto-rows: var(--hour-height);
   overflow: hidden;
 }
 
@@ -108,19 +112,31 @@ swp-grid-container {
 }
 
 /* Viewport/Track for slide animation */
-swp-header-viewport,
-swp-content-viewport {
+swp-header-viewport {
   overflow: hidden;
 }
 
-swp-header-track,
-swp-content-track {
+swp-content-viewport {
+  overflow: hidden;
+  min-height: 0; /* Tillader at krympe i grid */
+}
+
+swp-header-track {
   display: flex;
 }
 
-swp-header-track > swp-calendar-header,
+swp-content-track {
+  display: flex;
+  height: 100%;
+}
+
+swp-header-track > swp-calendar-header {
+  flex: 0 0 100%;
+}
+
 swp-content-track > swp-scrollable-content {
   flex: 0 0 100%;
+  height: 100%;
 }
 
 /* Header */
@@ -129,6 +145,16 @@ swp-calendar-header {
   grid-template-columns: repeat(var(--grid-columns), 1fr);
   grid-auto-rows: auto;
   background: var(--color-surface);
+  overflow-y: scroll;
+  overflow-x: hidden;
+}
+
+swp-calendar-header::-webkit-scrollbar {
+  background: transparent;
+}
+
+swp-calendar-header::-webkit-scrollbar-thumb {
+  background: transparent;
 }
 
 swp-calendar-header[data-levels="date"] > swp-day-header { grid-row: 1; }
@@ -182,7 +208,7 @@ swp-scrollable-content {
 swp-time-grid {
   display: block;
   position: relative;
-  min-height: calc(15 * var(--hour-height));
+  min-height: calc((var(--day-end-hour) - var(--day-start-hour)) * var(--hour-height));
 }
 
 swp-grid-lines {