Add SDK `getNftMetadata` and `getNftOwner` methods

[Levi-Ojukwu]

Description:

The contract has NFT query functions (query_nft_metadata and query_nft_owner at nft.rs:247-254) but the SDK does not expose them. These functions are essential for NFT marketplace features.

query_nft_metadata(env, invoice_id) returns Option<InvoiceNftMetadata> containing:

• invoice_id: u64
• amount: i128
• due_date: u32
• discount_rate: u32
• token: Address
• owner: Address
• minted_at: u32

query_nft_owner(env, invoice_id) returns Option<Address>.

Why it matters: NFT features require querying metadata and ownership.

Acceptance Criteria:

• Create getNftMetadata(invoiceId) returning InvoiceNftMetadata | null
• Create getNftOwner(invoiceId) returning string | null
• Add TypeScript types for NFT metadata
• Add tests

Relevant Files: contracts/invoice_liquidity/src/nft.rs:247-254, sdk/src/index.ts

---

[kuse-design]

i can resolve the issue because am a software engineer and am capable to solve this task

[Akanimoh12]

Hi, I'd love to work on this issue. I'm a full-stack blockchain developer specializing in web apps and Smart Contracts, with experience in Next.js, TypeScript, Tailwind, and blockchain integration's and writing tests. I can handle this confidently, here's my portfolio and key projects:

• https://frontend-nine-mocha.vercel.app/
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Active OSS contributor.

[vjuliaife]

I have experience working with TypeScript and SDK integrations and have reviewed the issue description. My approach will be to inspect the existing NFT query functions in the contract, follow the SDK's existing query patterns, add getNftMetadata and getNftOwner with the appropriate TypeScript types, and include tests to ensure the new methods behave correctly. I can submit a PR after validating the implementation against the project's existing conventions.

[grantfox-oss]

🦊 GrantFox — @Akanimoh12 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #423)
2. Your PR will be reviewed by the Invoice-Liquidity-Network maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@Akanimoh12's PR #450 was approved and merged by @Levi-Ojukwu.

🏆 @Akanimoh12: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (589 total points). Track your full progress on GrantFox.

👏 Great work, @Akanimoh12! Keep contributing to Invoice-Liquidity-Network.