feat(geo): real-time attendance map on OpenStreetMap tiles

New GeoAttendance scene plus Attendance Map chip on Landing. Uses
react-leaflet 4 + leaflet 1.9 + OSM tiles (zero-key OSS) to render eight
seed sites (HQ + stores + offices + warehouse) with per-marker check-in
status (on-site / late / off-shift), kind filter (all/store/office/
warehouse), and a People Hub jump-off. Auto-fits to the visible markers.

OSS stack: react-leaflet@4, leaflet@1.9.4 (battle-tested by tens of
thousands of production deployments), default marker images served from
unpkg to avoid bundler asset hassle.

src/scenes/Landing.tsx

@@ -79,6 +79,7 @@ export default function Landing() {
             <button className="hub-chip" onClick={() => setScene("hub-procurement")}>Procurement Hub</button>
             <button className="hub-chip" onClick={() => setScene("hub-hr")}>People Hub</button>
             <button className="hub-chip" onClick={() => setScene("hub-it")}>IT Hub</button>
+            <button className="hub-chip" onClick={() => setScene("geo-attendance")}>Attendance Map</button>
             <button className="hub-chip" onClick={() => setScene("agent")}>Talk to Pi</button>
             <button className="hub-chip" onClick={() => setScene("chat")}>Team Chat</button>
           </div>