[fix](trx-frontend-http): remove max-width constraint on statistics panel

The statistics tab had max-width: 72rem (1152px) while its parent .card
container uses --card-base-max-width: 1280px. This made the stats panel
visibly narrower than the header. Removing the constraint lets the panel
fill the card width like all other tab panels.

https://claude.ai/code/session_01SfhMwN8YKKEdA3f3JyfwUZ
Signed-off-by: Claude <noreply@anthropic.com>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -4982,7 +4982,6 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   flex-direction: column;
   gap: 1rem;
   padding: 1rem;
-  max-width: 72rem;
 }
 .stats-controls {
   display: flex;