web: unify empty + loading states behind EmptyState/InlineLoader

Replaces ad-hoc "Loading…" text and bare empty messages with two
shared feedback primitives that carry subtle lucide icons, consistent
muted-foreground/destructive tones, and a11y signaling (role=status,
aria-busy, role=alert on destructive empties). Loading copy gains
context ("Loading photos/folders/heaps/metadata…") and the right-
sidebar idle state moves from a "ⓘ" glyph to a MousePointerClick
icon. SkeletonGrid stays as the initial-grid loader.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/lib/components/timeline/BulkActionBar.svelte

@@ -22,6 +22,8 @@
 	import { filters } from '$lib/stores/filters.svelte';
 	import { push as pushUndo } from '$lib/stores/undo.svelte';
 	import { isAuthenticated } from '$lib/stores/session.svelte';
+	import { EmptyState, InlineLoader } from '$lib/components/feedback';
+	import { Layers } from 'lucide-svelte';
 
 	const qc = useQueryClient();
 	let busy = $state(false);
@@ -288,9 +290,9 @@
 							class="absolute bottom-full right-0 mb-2 max-h-72 w-56 overflow-y-auto rounded-md border border-border bg-background p-1 text-xs shadow-lg"
 						>
 							{#if heapsQuery.isPending}
-								<p class="px-2 py-1 text-muted-foreground">Loading…</p>
+								<InlineLoader size="sm" label="Loading heaps…" />
 							{:else if (heapsQuery.data ?? []).length === 0}
-								<p class="px-2 py-1 text-muted-foreground">No heaps yet</p>
+								<EmptyState size="compact" icon={Layers} title="No heaps yet" />
 							{:else}
 								{#each heapsQuery.data ?? [] as heap, i (heap.UID)}
 									<button