Implement proper blockchain smart contract integration replace simulation placeholder with real Web3 calls

[nanaf6203-bit]

Problem

The BlockchainService contains simulation methods producing fake transaction hashes. The smart contract ABI exists but is never deployed or used. Ethers.js is a dependency but never called.

Expected Outcome

Service connects to real blockchain networks and records/verifies transactions.

Acceptance Criteria

• Smart contract deployable via migration script
• recordTransactionOnBlockchain submits real transactions
• verifyBlockchainTransaction queries on-chain data
• Fallback to local mode when blockchain unavailable

Files Affected

src/blockchain/blockchain.service.ts, src/blockchain/contracts/PropertyTransaction.json, src/blockchain/blockchain.module.ts

Difficulty

Hard

Estimated Effort

Large (2-3 weeks)

Labels

blockchain, feature, smart-contracts

[nafiuishaaq]

@nafiuishaaq has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello maintainer, i can take care of this within 2 hours once assigned. Thank you.

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

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[drips-wave]

This issue has been completed by @nafiuishaaq as part of the Stellar Wave Program's 7th Wave 🥳

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