refactor: split types.ts into per-exchange type modules

- Extract GRVT-specific types to grvt/types.ts
- Extract Aster-spot/futures types to aster/types.ts
- types.ts now contains only universal/platform-agnostic types
- Reduced from 632 to ~135 lines

src/exchanges/grvt/gateway.ts

@@ -31,13 +31,15 @@ import type {
   Ticker,
   CreateOrderParams,
   OrderSide,
+} from "../types";
+import type {
   GrvtSignedOrder,
   GrvtSignature,
   GrvtUnsignedOrder,
   GrvtTimeInForce,
   GrvtOrderMetadataInput,
   GrvtTriggerMetadata,
-} from "../types";
+} from "./types";
 
 const DEFAULT_ACCOUNT_POLL_INTERVAL_MS = 5000;
 const DEFAULT_ORDERS_POLL_INTERVAL_MS = 2500;