fix(frontend): admin section fixes (pagination, actions, navbar)

- Audit log: replace load-more with page-based pagination
- Audit log: add all 29 action types to the dropdown
- Audit log: fix pagination bar hidden behind footer
- Root layout: hide footer navbar on /admin/* routes
- Users pages: fix curly-quote parse error in ConfirmDialog messages

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

frontend/src/routes/admin/users/+page.svelte

@@ -172,7 +172,7 @@
 
 {#if confirmDeleteUser}
 	<ConfirmDialog
-		message="Delete user "{confirmDeleteUser.name}"? This cannot be undone."
+		message="Delete user &ldquo;{confirmDeleteUser.name}&rdquo;? This cannot be undone."
 		confirmLabel="Delete"
 		danger
 		onConfirm={() => deleteUser(confirmDeleteUser!)}

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

@@ -150,7 +150,7 @@
 
 {#if confirmDelete && user}
 	<ConfirmDialog
-		message="Delete user "{user.name}"? This cannot be undone."
+		message="Delete user &ldquo;{user.name}&rdquo;? This cannot be undone."
 		confirmLabel="Delete"
 		danger
 		onConfirm={doDelete}