refactor: new timeline component

- Create new timeline component (extracted from asset-gird) without removing old code
- Add timeline/, timeline/actions/, timeline/base-components/, and timeline/internal-components/ directories
- Copy needed components (delete-asset-dialog, scrubber, skeleton) to new locations
- Add new timeline components (base-timeline, base-timeline-viewer, timeline-month, etc.)
- Update timeline-util.ts with new functions (findMonthAtScrollPosition, formatGroupTitleFull)
- Add asset-viewer-actions and asset-viewer-and-actions components

This allows the timeline to exist alongside the current AssetGrid component.

web/src/lib/managers/timeline-manager/day-group.svelte.ts

@@ -13,6 +13,7 @@ export class DayGroup {
   readonly monthGroup: MonthGroup;
   readonly index: number;
   readonly groupTitle: string;
+  readonly groupTitleFull: string;
   readonly day: number;
   viewerAssets: ViewerAsset[] = $state([]);
 
@@ -26,11 +27,12 @@ export class DayGroup {
   #col = $state(0);
   #deferredLayout = false;
 
-  constructor(monthGroup: MonthGroup, index: number, day: number, groupTitle: string) {
+  constructor(monthGroup: MonthGroup, index: number, day: number, groupTitle: string, groupTitleFull: string) {
     this.index = index;
     this.monthGroup = monthGroup;
     this.day = day;
     this.groupTitle = groupTitle;
+    this.groupTitleFull = groupTitleFull;
   }
 
   get top() {