fix: referral network graph rendering and layout

- fix top offset breakpoint: sm:top-14 → lg:top-14 to match AppShell
  header visibility (mobile header is lg:hidden with h-16)
- add gravity to FA2 layout to prevent disconnected nodes from flying
  to extreme positions, making auto-rescale shrink everything to dots
- clamp outlier node positions after FA2 finishes (3σ threshold)
- add ResizeObserver to sync sigma canvas with container size changes
- call sigma.resize() before camera reset after FA2
- increase node sizes: user min 8→12, max 40→50, campaign 18→24
- reduce FA2 duration 5s→3s and slowDown 5→2 for tighter layout

src/pages/ReferralNetwork/utils.ts

@@ -46,8 +46,8 @@ export function getUserNodeColor(
  * Size is proportional to direct_referrals, clamped between min and max.
  */
 export function getUserNodeSize(directReferrals: number): number {
-  const MIN_SIZE = 8;
-  const MAX_SIZE = 40;
+  const MIN_SIZE = 12;
+  const MAX_SIZE = 50;
   if (directReferrals === 0) return MIN_SIZE;
   return Math.min(MAX_SIZE, MIN_SIZE + Math.sqrt(directReferrals) * 5);
 }