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/elements/HotModuleReload.svelte

@@ -1,36 +1,18 @@
 <script lang="ts">
-  import { onDestroy, onMount } from 'svelte';
+  import { onMount } from 'svelte';
   import type { UpdatePayload } from 'vite';
 
-  type Props = {
-    onBeforeUpdate?: (payload: UpdatePayload) => void;
-    onAfterUpdate?: (payload: UpdatePayload) => void;
-  };
+  interface Props {
+    onAfterUpdate: (payload: UpdatePayload) => void;
+  }
 
-  let { onBeforeUpdate, onAfterUpdate }: Props = $props();
-
-  const unsubscribes: (() => void)[] = [];
+  let { onAfterUpdate }: Props = $props();
 
   onMount(() => {
     const hot = import.meta.hot;
-    if (!hot) {
-      return;
-    }
-
-    if (onBeforeUpdate) {
-      hot.on('vite:beforeUpdate', onBeforeUpdate);
-      unsubscribes.push(() => hot.off('vite:beforeUpdate', onBeforeUpdate));
-    }
-
-    if (onAfterUpdate) {
+    if (hot) {
       hot.on('vite:afterUpdate', onAfterUpdate);
-      unsubscribes.push(() => hot.off('vite:afterUpdate', onAfterUpdate));
-    }
-  });
-
-  onDestroy(() => {
-    for (const unsubscribe of unsubscribes) {
-      unsubscribe();
+      return () => hot.off('vite:afterUpdate', onAfterUpdate);
     }
   });
 </script>