fix(dashboard): show org switcher for superadmin users

[zbigniewsobiecki]

Summary

• Fix org switcher not appearing for superadmin users
• The isAdmin check in org-context.tsx only checked for role === 'admin', missing superadmin

Root Cause

// Before (bug)
const isAdmin = me?.role === 'admin';

// After (fix)
const isAdmin = me?.role === 'admin' || me?.role === 'superadmin';

Test plan

• TypeScript compiles
• Lint passes
• All 3727 tests pass
• Manually verify superadmin can see and use org switcher after deployment

🤖 Generated with Claude Code