docs: add note on transformations registration (#10523)

add note on transformations registration

Author: runspired

guides/the-manual/schemas/transformations.md

@@ -115,6 +115,17 @@ user.netWorth = 2_500_000.005;
 
 The `type` field in the schema entry matches the `[Type]` symbol on the transformation object — just as with derivations.
 
+::: tip Registering without `useRecommendedStore`
+If you're not using `useRecommendedStore`, register transformations imperatively before any schema that references them is registered:
+
+```ts
+import { PriceTransform } from './transformations/price';
+store.schema.registerTransformation(PriceTransform);
+```
+
+See [`SchemaService.registerTransformation`](https://api.warp-drive.io/interfaces/SchemaService.html#registertransformation) in the API reference.
+:::
+
 ## Two-Way Conversion
 
 The full round-trip for a transformed field: