refactor: move document domain core to lib/document/

Moves ~25 components, utils (search, filename, groupDocuments,
documentStatusLabel, validateFile), bulkSelection store, and
TranscriptionSection sub-component. Fixes broken relative imports.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/document/BulkSelectionBar.svelte

@@ -0,0 +1,74 @@
+<script lang="ts">
+import { goto } from '$app/navigation';
+import { m } from '$lib/paraglide/messages.js';
+import { bulkSelectionStore } from '$lib/document/bulkSelection.svelte';
+
+let { canWrite }: { canWrite: boolean } = $props();
+
+const count = $derived(bulkSelectionStore.size);
+const visible = $derived(canWrite && count > 0);
+
+function openBulkEdit() {
+	goto('/documents/bulk-edit');
+}
+
+function clearAll() {
+	bulkSelectionStore.clear();
+}
+
+// Escape clears the selection — keyboard escape hatch when the user has
+// drilled into a 50-row selection and wants to bail without Tab-ing through
+// the whole footer (WCAG 2.1.1). Bails when an open dialog, expanded menu,
+// or popover is in front so we don't steal Esc from NotificationBell,
+// ConfirmDialog, HelpPopover, etc.
+function onEscape(e: KeyboardEvent) {
+	if (e.key !== 'Escape' || !visible) return;
+	if (e.defaultPrevented) return;
+	const overlay = document.querySelector(
+		'dialog[open], [aria-expanded="true"], [role="menu"]:not([hidden]), [role="dialog"]:not([hidden])'
+	);
+	if (overlay) return;
+	clearAll();
+}
+</script>
+
+<svelte:window onkeydown={onEscape} />
+
+{#if visible}
+	<div
+		data-testid="bulk-selection-bar"
+		class="fixed right-0 bottom-0 left-0 z-30 flex items-center justify-between gap-3 border-t border-line bg-surface px-4 py-3 pb-[max(0.75rem,env(safe-area-inset-bottom))] shadow-[0_-2px_8px_rgba(0,0,0,0.06)] sm:px-6"
+	>
+		<div class="flex items-baseline gap-3">
+			<span
+				class="font-sans text-sm font-medium text-ink"
+				data-testid="bulk-selection-count"
+				aria-live="polite"
+				aria-atomic="true"
+			>
+				{count === 1 ? m.bulk_edit_n_selected_one() : m.bulk_edit_n_selected_other({ count })}
+			</span>
+			<span class="hidden font-sans text-xs text-ink-3 sm:inline">
+				{m.bulk_edit_clear_hint_keyboard()}
+			</span>
+		</div>
+		<div class="flex items-center gap-2">
+			<button
+				type="button"
+				onclick={clearAll}
+				class="inline-flex min-h-[44px] items-center px-4 py-2 font-sans text-sm font-medium text-ink-2 transition-colors hover:text-ink"
+				data-testid="bulk-clear-all"
+			>
+				{m.bulk_edit_clear_selection()}
+			</button>
+			<button
+				type="button"
+				onclick={openBulkEdit}
+				class="inline-flex min-h-[44px] items-center bg-primary px-5 py-2 font-sans text-xs font-bold tracking-widest text-primary-fg uppercase transition-colors hover:bg-primary/90"
+				data-testid="bulk-edit-open"
+			>
+				{m.bulk_edit_button()}
+			</button>
+		</div>
+	</div>
+{/if}