feat(prototype): crossing patrol routes and through-transit objects

Mobile obstacles used to bounce until they wedged into far corners, and
a single perimeter route let the mesh stretch into segments that stopped
exchanging data. Even drones now fly the perimeter while odd drones fly
an X through the center, keeping bridge links alive, and transit objects
enter at one edge, cross the area, and respawn at a fresh edge.

prototype/src/App.tsx

@@ -141,7 +141,7 @@ export default function App(): JSX.Element {
               />
               {ob.moving && (
                 <text x={sx(ob.pos.x)} y={sy(ob.pos.y) + 4} style={styles.obLabel as never}>
-                  mobile
+                  transit
                 </text>
               )}
             </g>
@@ -186,7 +186,7 @@ export default function App(): JSX.Element {
             <div style={styles.dim}>blue line — pose broadcast (5 Hz, ~46 B)</div>
             <div style={styles.dim}>green line — bulk sync (sealed partitions)</div>
             <div style={styles.dim}>flash — broadcast event delivered</div>
-            <div style={styles.dim}>red circle — mobile obstacle</div>
+            <div style={styles.dim}>red circle — transit object crossing the area</div>
           </Section>
         </aside>
       </div>