feat(frontend): Service to load EXT NFTs

[AntonioVentilii]

Motivation

Similar to what we have for ERC NFTs, we create a service to load EXT NFTs.

[Copilot]

Pull request overview

This PR implements a service to load EXT NFTs for ICP (Internet Computer Protocol), mirroring the existing functionality for ERC NFTs on Ethereum. The implementation adds utility functions to map EXT token data to NFT objects, a service layer to fetch NFTs from multiple collections, and comprehensive test coverage for both utilities and services.

Key changes:

• Added loadNfts service to fetch EXT NFTs from multiple token collections for a given identity
• Created mapExtNft utility to transform EXT token indices into standardized NFT objects with proper identifiers and image URLs
• Introduced IcNonFungibleToken type to represent ICP-based NFTs in the type system

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/frontend/src/icp/services/nft.services.ts	New service implementing NFT loading logic with error handling for multiple EXT token collections
src/frontend/src/icp/utils/nft.utils.ts	Utility functions to map EXT token data to standardized NFT format with collection metadata
src/frontend/src/icp/types/nft.ts	Type definition for ICP non-fungible tokens (currently only ExtToken)
src/frontend/src/lib/types/nft.ts	Updated NonFungibleToken union type to include IcNonFungibleToken instead of ExtToken directly
src/frontend/src/tests/icp/services/nft.services.spec.ts	Comprehensive tests for loadNfts service covering edge cases and error handling
src/frontend/src/tests/icp/utils/nft.utils.spec.ts	Tests for mapExtNft utility including validation of negative indices
src/frontend/src/tests/mocks/ext-tokens.mock.ts	Added second mock EXT token for testing multiple collection scenarios

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