feat(stats): put the region backfill right on the stats page

The admin backfill lived only in Settings -> Advanced, so an admin staring at
the 'Uncategorised' row had no obvious way to fix it. Render the admin-only
RegionBackfillCard inline in the region section when uncategorised > 0, and
clarify the zero-state (remaining untagged pins belong to other mappers).

src/components/RegionBackfillCard.tsx

@@ -80,7 +80,8 @@ export function RegionBackfillCard() {
           <p className="text-xs text-muted-foreground">Scanning your spots…</p>
         ) : count === 0 ? (
           <p className="text-xs text-[#ccff00]">
-            Every spot &amp; shop you own already has a region tag. 🎉
+            Every spot &amp; shop you own already has a region tag. 🎉 Any remaining
+            “Uncategorised” pins belong to other mappers — only their own keys can tag them.
           </p>
         ) : (
           <>

src/pages/CommunityStatsPage.tsx

@@ -7,6 +7,7 @@ import { useAuthor } from '@/hooks/useAuthor';
 import { genUserName } from '@/lib/genUserName';
 import { Avatar, AvatarImage, AvatarFallback } from '@/components/ui/avatar';
 import { useGrowthStats } from '@/hooks/useGrowthStats';
+import { RegionBackfillCard } from '@/components/RegionBackfillCard';
 import { cn } from '@/lib/utils';
 import { formatAge } from '@/lib/routeCache';
 
@@ -449,6 +450,9 @@ export default function CommunityStatsPage() {
                 <> <strong className="text-gray-500">{uncategorised} of {locationsTotal}</strong> location{locationsTotal === 1 ? '' : 's'} have no location tag and show as “Uncategorised”.</>
               )}
             </p>
+            {/* Admin-only (renders null otherwise): fix the gap right where it
+                shows up — re-derive region tags for the viewer's own legacy pins. */}
+            {uncategorised > 0 && <div className="mt-4"><RegionBackfillCard /></div>}
           </section>
         )}