feat: Add KnownCaipNamespacedChainId type (#258)

This commit adds a type for CAIP chain IDs that are namespaced by a
known CAIP namespace.

This type enables the usage of safer literal string types for namespaced
CAIP chain IDs, and is intended as a narrower alternative to
`CaipChainId`.

---------

Co-authored-by: Eric Wolff <erwolff@gmail.com>

Author: MajorLift

src/caip-types.ts

@@ -142,6 +142,15 @@ export enum KnownCaipNamespace {
   Wallet = 'wallet',
 }
 
+/**
+ * A CAIP-2 chain ID that is guaranteed to have a known CAIP namespace
+ * (@see {@link KnownCaipNamespace}).
+ *
+ * This is a narrower, more type-safe alternative to {@link CaipChainId} for use cases
+ * where the chain namespace must be one of the known standards.
+ */
+export type KnownCaipNamespacedChainId = `${KnownCaipNamespace}:${string}`;
+
 /**
  * Check if the given value is a {@link CaipChainId}.
  *