fix(#221): suppress tagQ when tags are already selected

Sending tagQ alongside selected tags caused an unintended AND: documents
had to match both the selected-tag filter and the partial-name filter,
making the list shrink while the user was still typing a new tag.

tagQ is now only forwarded to the backend when no tags are selected,
which is the only case where the live partial-filter is meaningful.

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

frontend/src/routes/+page.server.ts

@@ -48,7 +48,7 @@ export async function load({ url, fetch }) {
 								senderId: senderId || undefined,
 								receiverId: receiverId || undefined,
 								tag: tags.length ? tags : undefined,
-								tagQ: tagQ || undefined,
+								tagQ: tagQ && !tags.length ? tagQ : undefined,
 								tagOp: tagOp === 'OR' ? 'OR' : undefined,
 								sort,
 								dir: dir || undefined
@@ -64,7 +64,6 @@ export async function load({ url, fetch }) {
 		if (docsResult && docsResult.response.status === 401) {
 			throw redirect(302, '/login');
 		}
-
 		const searchResult = docsResult?.data as {
 			documents?: Document[];
 			total?: number;