add pixel stacking

packages/client/src/components/CanvasMeta.tsx

packages/client/src/contexts/AppContext.tsx

packages/client/src/lib/canvas.ts

packages/client/src/lib/network.ts

packages/lib/src/canvas.ts

packages/lib/src/net.ts

packages/server/prisma/dbml/schema.dbml

...es/server/prisma/migrations/20240304215631_/migration.sql

...es/server/prisma/migrations/20240304220059_/migration.sql

packages/server/prisma/schema.prisma

packages/server/src/lib/Canvas.ts

packages/server/src/lib/SocketServer.ts

packages/server/src/lib/redis.ts

packages/server/src/models/User.ts