Add WebSocket handshake delay to fix timing issue

- Add 10ms delay after successful WebSocket handshake
- Use std.posix.nanosleep for proper timing
- This should prevent 'client sent data before handshake complete' error
- CLI WebSocket implementation improved but needs server testing

Status: WebSocket handshake timing improved, ready for testing

cli/src/net/ws.zig

@@ -217,6 +217,9 @@ pub const Client = struct {
                 return error.HandshakeFailed;
             }
         }
+
+        // Add small delay to ensure server is ready for WebSocket frames
+        std.posix.nanosleep(0, 10 * std.time.ns_per_ms);
     }
 
     fn generateWebSocketKey(allocator: std.mem.Allocator) ![]u8 {