feat(backend): Implement IPFS metadata storage for escrow records

[KuchiMercy]

Description

IPFS module has controller/service stubs. Implement metadata hashing, IPFS pinning, and verification for tamper-proof records.

Module: src/modules/ipfs/

Acceptance Criteria

• IpfsService: pinMetadata, getMetadata, verifyMetadata
• Metadata schema: escrowId, buyer, seller, amount, asset, conditions, deadline, status, metadataHash
• SHA-256 hash before pinning, store hash on escrow entity
• Pin at lifecycle events: creation, funding, completion, dispute
• ipfsCid and ipfsMetadataHash fields on Escrow entity
• GET /escrows/:id/metadata, /metadata/verify
• POST /escrows/:id/metadata/pin (admin only)
• Configurable provider: local IPFS or Pinata (IPFS_PROVIDER env)
• Graceful failure: retry once, log error, don't block
• Metadata versioning (new CID per pin)
• Unit and integration tests

Points: 200

[Chrisbankz0]

@Chrisbankz0 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, I’m a full stack developer with hands-on experience building with variety of tools including Nextjs, nodejs, nestjs, React, Typescript and more

I focus on writing clear, maintainable code and making sure features work as expected end to end, not just in isolation. I communicate progress regularly and keep things transparent as I work. I’m confident I can complete this task within an ETA of 4 HOURS

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Chrisbankz0 to this issue.

[debbieAmoni]

@debbieAmoni has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hi maintainer , please i would love to work on this issue , i can work on it immediately

ℹ️ Repo Maintainers: To accept this application, review their application or assign @debbieAmoni to this issue.

[ohamamarachi474-del]

@ohamamarachi474-del has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hi maintainer, ican i work on this ????

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ohamamarachi474-del to this issue.

[ObedChibunna]

@ObedChibunna has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I'll like to work on this issue. Kindly assign

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ObedChibunna to this issue.

[drips-wave]

Congratulations, @ObedChibunna! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @ObedChibunna: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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