feat(ui): hide write UI from users without WRITE_ALL permission

Wrap write-only elements with {#if data.canWrite} in:
- Home page: Neues Dokument link
- Persons list: Neue Person link
- Document detail: Bearbeiten button
- Person detail: edit button, edit form, merge section

Refs #17
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/+page.svelte

@@ -191,6 +191,7 @@ $effect(() => {
 
 	<!-- DOCUMENT LIST HEADER -->
 	<div class="mb-2 flex justify-end">
+		{#if data.canWrite}
 		<a
 			href="/documents/new"
 			class="inline-flex items-center gap-1 text-sm font-medium text-brand-navy/60 transition-colors hover:text-brand-navy"
@@ -198,6 +199,7 @@ $effect(() => {
 			<img src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Add/Add-General-MD.svg" alt="" aria-hidden="true" class="h-4 w-4" />
 			{m.docs_btn_new()}
 		</a>
+		{/if}
 	</div>
 
 	<!-- DOCUMENT LIST -->

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

@@ -74,6 +74,7 @@
 		</div>
 
 		<div class="flex items-center gap-3 flex-shrink-0 ml-4 font-sans">
+			{#if data.canWrite}
 			<a
 				href="/documents/{doc.id}/edit"
 				class="text-brand-navy bg-transparent border border-brand-navy hover:bg-brand-navy hover:text-white px-4 py-2 rounded text-sm font-medium transition flex items-center gap-2"
@@ -81,6 +82,7 @@
 				<img src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Edit-Content-MD.svg" alt="" aria-hidden="true" class="w-4 h-4" />
 				{m.btn_edit()}
 			</a>
+			{/if}
 
 			{#if doc.filePath}
 				<a

frontend/src/routes/page.svelte.spec.ts

@@ -17,6 +17,7 @@ vi.stubGlobal(
 
 const emptyData = {
 	user: undefined,
+	canWrite: true,
 	filters: { q: '', from: '', to: '', senderId: '', receiverId: '', tags: [] },
 	documents: [],
 	initialValues: { senderName: '', receiverName: '' },

frontend/src/routes/persons/+page.svelte

@@ -25,6 +25,7 @@ function handleSearch(e: Event) {
 			<p class="mt-2 max-w-xl font-sans text-sm text-brand-navy/60">
 				{m.persons_subtitle()}
 			</p>
+			{#if data.canWrite}
 			<a
 				href="/persons/new"
 				class="mt-3 inline-flex items-center gap-1 text-sm font-medium text-brand-navy/60 transition-colors hover:text-brand-navy"
@@ -32,6 +33,7 @@ function handleSearch(e: Event) {
 				<img src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Add/Add-General-MD.svg" alt="" aria-hidden="true" class="h-4 w-4" />
 				{m.persons_btn_new()}
 			</a>
+			{/if}
 		</div>
 
 		<!-- Search Input -->

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

@@ -81,7 +81,7 @@
         <div class="h-2 bg-brand-navy w-full"></div>
 
         <div class="p-8 md:p-10">
-            {#if editMode}
+            {#if editMode && data.canWrite}
                 <!-- Edit Form -->
                 <form method="POST" action="?/update" use:enhance>
                     <div class="flex flex-col gap-6">
@@ -191,10 +191,12 @@
                                     <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 12h.01M12 12h.01M16 12h.01M21 12c0 4.418-4.03 8-9 8a9.863 9.863 0 01-4.255-.949L3 20l1.395-3.72C3.512 15.042 3 13.574 3 12c0-4.418 4.03-8 9-8s9 3.582 9 8z"/></svg>
                                     {m.person_btn_conversations()}
                                 </a>
+                                {#if data.canWrite}
                                 <button onclick={() => (editMode = true)} class="inline-flex items-center gap-1.5 px-3 py-1.5 text-xs font-bold uppercase tracking-widest border border-gray-300 text-gray-500 rounded hover:border-brand-navy hover:text-brand-navy transition-colors">
                                     <img src="/degruyter-icons/Simple/Small-16px/SVG/Action/Edit-Content-SM.svg" alt="" aria-hidden="true" class="w-3.5 h-3.5" />
                                     {m.btn_edit()}
                                 </button>
+                                {/if}
                             </div>
                         </div>
 
@@ -236,6 +238,7 @@
     </div>
 
     <!-- Merge Section -->
+    {#if data.canWrite}
     {#key person.id}
     <div class="bg-white shadow-sm border border-brand-sand rounded-sm overflow-hidden mb-10">
         <div class="p-6 md:p-8">
@@ -298,6 +301,7 @@
         </div>
     </div>
     {/key}
+    {/if}
 
     <!-- Co-Correspondents Section -->
     {#if coCorrespondents().length > 0}