fix(nav): remove opacity reduction from local players

Remove the opacity: 0.6 style that was making local players appear
greyed out during network games. This was creating an inconsistent
appearance where network players looked vibrant but local players
looked faded.

The pointer-events property already prevents interaction when players
can't be modified, so the visual opacity hint was redundant and
confusing.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/components/nav/GameContextNav.tsx

@@ -251,7 +251,6 @@ export function GameContextNav({
                 : '0 4px 12px rgba(0, 0, 0, 0.1)',
               transition: 'all 0.4s cubic-bezier(0.4, 0, 0.2, 1)',
               transform: shouldEmphasize ? 'scale(1.05)' : 'scale(1)',
-              opacity: canModifyPlayers ? 1 : 0.6,
               pointerEvents: canModifyPlayers ? 'auto' : 'none',
             }}
           >