fix(frontend): always start with panel closed on document open

Removed localStorage persistence for the open/closed state so the PDF
is always visible first when navigating to a document. Height and active
tab are still remembered across visits.

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

frontend/src/routes/documents/[id]/+page.svelte

@@ -73,7 +73,6 @@ $effect(() => {
 
 // ── Bottom panel state ────────────────────────────────────────────────────────
 
-const LS_KEY_OPEN = 'doc-panel-open';
 const LS_KEY_HEIGHT = 'doc-panel-height';
 const LS_KEY_TAB = 'doc-panel-tab';
 
@@ -86,7 +85,6 @@ let localStorageRestored = $state(false);
 onMount(() => {
 	navHeight = document.querySelector('header')?.getBoundingClientRect().height ?? 0;
 
-	const savedOpen = localStorage.getItem(LS_KEY_OPEN);
 	const savedHeight = localStorage.getItem(LS_KEY_HEIGHT);
 	const savedTab = localStorage.getItem(LS_KEY_TAB);
 
@@ -99,13 +97,6 @@ onMount(() => {
 		const h = parseInt(savedHeight, 10);
 		if (!isNaN(h) && h >= 80) panelHeight = h;
 	}
-	if (savedOpen !== null) {
-		panelOpen = savedOpen === 'true';
-	} else if (!doc.filePath) {
-		// No previous state and no file → open to Metadaten by default
-		panelOpen = true;
-		activeTab = 'metadata';
-	}
 
 	localStorageRestored = true;
 
@@ -126,7 +117,6 @@ onMount(() => {
 // Persist panel state whenever it changes (after initial restore).
 $effect(() => {
 	if (!localStorageRestored) return;
-	localStorage.setItem(LS_KEY_OPEN, String(panelOpen));
 	localStorage.setItem(LS_KEY_HEIGHT, String(panelHeight));
 	localStorage.setItem(LS_KEY_TAB, activeTab);
 });