Implement Core BitLock Contract with NFT Marketplace and Staking Functionality

[timileyin-create]

Overview

This PR introduces the foundational components for BitLock – a Bitcoin-backed NFT exchange protocol on Stacks L2. It enables:
✅ Collateralized NFT Minting
✅ Decentralized Marketplace
✅ Fractional Ownership
✅ Yield-Generating Staking

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Key Changes

1. Core Contract Architecture (feat: Initialize BitLock contract)

• Data Structures

  (define-map tokens {token-id: uint} {
    owner: principal,
    uri: (string-ascii 256),
    collateral: uint,
    is-staked: bool,
    stake-timestamp: uint,
    fractional-shares: uint
  })

• Protocol Constants
  • min-collateral-ratio: 150%
  • protocol-fee: 2.5%
  • yield-rate: 5% APY

2. NFT Lifecycle Management (feat: Add mint-nft)

• Collateral Verification

  (asserts! (>= (stx-get-balance tx-sender) collateral-requirement) 

• Metadata Validation
  • URI length/format checks
  • Atomic BTC-STX collateral transfers

3. Marketplace Engine (feat: Implement NFT transfer...)

• Atomic Swaps
  • Seller/Buyer STX transfers with fee deduction

  (try! (stx-transfer? (/ (* price protocol-fee) 1000) tx-sender contract-owner))

• Fractionalization
  • Share tracking with proportional ownership rights

4. Staking Module (feat: Implement staking...)

• Time-Based Yield

  (let ((blocks-staked (- block-height stake-timestamp)))
    (* blocks-staked (/ yield-rate 52560))) ;; Annual blocks estimate

• Auto-Claim Mechanism
  • Rewards distributed atomically during unstaking

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Compliance Alignment

1. Bitcoin Standards
   • BRC-20 compatible metadata structure
   • sBTC collateral tracking
2. Financial Safeguards
   • Time-locked staking withdrawals
   • Anti-frontrunning listing logic

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Reviewer Notes

• Critical Path: Verify collateral ratio enforcement in mint-nft
• QA Focus: Staking reward calculation edge cases
• Compliance Check: Validate fee distribution addresses