fix(admin-tags): name clears after save and wrong confirmation text

SvelteKit's use:enhance resets the form after a successful action.
The name input used value={data.tag.name} without bind:, so Svelte 5's
fine-grained reactivity did not re-apply the unchanged value after the
reset — leaving the field empty. Passing reset: false to update() fixes
this.

Also corrected the confirmation message from "renamed" to "saved" in
all three locales, since the action updates name, parent, and color.

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

frontend/src/routes/admin/tags/[id]/+page.svelte

@@ -119,7 +119,7 @@ const colors = [
 			id="edit-tag-form"
 			method="POST"
 			action="?/update"
-			use:enhance
+			use:enhance={() => async ({ update }) => { await update({ reset: false }); }}
 			oninput={unsaved.markDirty}
 			class="mb-5"
 		>