refactor(documents): drop documentLocation binding from edit layouts; wire archive fields

frontend/src/lib/components/document/BulkDocumentEditLayout.svelte

@@ -67,7 +67,6 @@ let selectedReceivers = $state<Person[]>(untrack(() => initialReceivers));
 let dateIso = $state('');
 let tags = $state<Tag[]>([]);
 // Bulk-edit only — replace-on-non-blank semantics.
-let documentLocation = $state('');
 let archiveBox = $state('');
 let archiveFolder = $state('');
 
@@ -231,7 +230,6 @@ async function saveBulkEdit() {
 		tagNames: tags.map((t) => t.name),
 		senderId: senderId || null,
 		receiverIds: selectedReceivers.map((r) => r.id),
-		documentLocation: documentLocation || null,
 		archiveBox: archiveBox || null,
 		archiveFolder: archiveFolder || null
 	};
@@ -442,7 +440,6 @@ async function retrySave() {
 						/>
 						<DescriptionSection
 							bind:tags={tags}
-							bind:documentLocation={documentLocation}
 							bind:archiveBox={archiveBox}
 							bind:archiveFolder={archiveFolder}
 							hideTitle
@@ -494,7 +491,6 @@ async function retrySave() {
 					/>
 					<DescriptionSection
 						bind:tags={tags}
-						bind:documentLocation={documentLocation}
 						bind:archiveBox={archiveBox}
 						bind:archiveFolder={archiveFolder}
 						hideTitle