feat(frontend): Use Zod for Token type (#3252)

# Motivation

We ultimately use `Zod` for `Token` type. That requires a few more
sub-interfaces to use `Zod` too (for example the ones related to
OnRamper).

src/frontend/src/lib/types/network.ts

@@ -16,7 +16,7 @@ const NetworkAppMetadataSchema = z.object({
 	explorerUrl: UrlSchema
 });
 
-const NetworkSchema = z.object({
+export const NetworkSchema = z.object({
 	id: NetworkIdSchema,
 	env: NetworkEnvironmentSchema,
 	name: z.string(),

src/frontend/src/lib/types/token.ts

@@ -1,5 +1,5 @@
 import type { OptionBalance } from '$lib/types/balance';
-import type { Network } from '$lib/types/network';
+import { NetworkSchema } from '$lib/types/network';
 import type { OnramperId } from '$lib/types/onramper';
 import type { AtLeastOne, Option, RequiredExcept } from '$lib/types/utils';
 import { z } from 'zod';
@@ -31,32 +31,41 @@ const TokenAppearanceSchema = z.object({
 	oisyName: TokenOisyNameSchema.optional()
 });
 
+// TODO: use Zod to validate the OnramperId
+const TokenBuySchema = z.object({
+	onramperId: z.custom<OnramperId>().optional()
+});
+
+const TokenBuyableSchema = z.object({
+	buy: z.custom<AtLeastOne<TokenBuy>>().optional()
+});
+
+const TokenSchema = z
+	.object({
+		id: TokenIdSchema,
+		network: NetworkSchema,
+		standard: TokenStandardSchema,
+		category: TokenCategorySchema
+	})
+	.merge(TokenMetadataSchema)
+	.merge(TokenAppearanceSchema)
+	.merge(TokenBuyableSchema);
+
 export type TokenId = z.infer<typeof TokenIdSchema>;
 
 export type TokenStandard = z.infer<typeof TokenStandardSchema>;
 
 export type TokenCategory = z.infer<typeof TokenCategorySchema>;
 
-export type Token = {
-	id: TokenId;
-	network: Network;
-	standard: TokenStandard;
-	category: TokenCategory;
-} & TokenMetadata &
-	TokenAppearance &
-	TokenBuyable;
+export type Token = z.infer<typeof TokenSchema>;
 
 export type TokenMetadata = z.infer<typeof TokenMetadataSchema>;
 
 export type TokenAppearance = z.infer<typeof TokenAppearanceSchema>;
 
-export interface TokenBuyable {
-	buy?: AtLeastOne<TokenBuy>;
-}
+export type TokenBuyable = z.infer<typeof TokenBuyableSchema>;
 
-export interface TokenBuy {
-	onramperId?: OnramperId;
-}
+export type TokenBuy = z.infer<typeof TokenBuySchema>;
 
 export interface TokenLinkedData {
 	twinTokenSymbol?: string;