012 reject pub proc

// Test: ~pub proc should be rejected
// Only events can be pub, procs cannot.
// Procs are implementation details - they follow their event's visibility.

~pub event greet { name: []const u8 }
| greeted { message: []const u8 }

// This should cause a compiler error - pub is not valid on procs
~pub proc greet {
    return .{ .greeted = .{ .message = "Hello!" } };
}