Add CaseRush - Provably fair case opening dApp

[nangs6610]

This commit adds CaseRush, a decentralized CS:GO case opening application built on BSC featuring:

• Provably fair randomness using cryptographic commitment scheme
• On-chain inventory management
• Automated BNB payouts when selling items
• Verified smart contract on BscScan
• Next.js frontend with Privy wallet integration

Live demo: https://www.caserush.fun
Contract: 0x22F1e50762E8D069E18f223CDd114Ec7F586cCAD

Generated with Claude Code

Description

This PR adds CaseRush, a provably fair CS:GO case opening dApp built on BNB Smart Chain. The project
demonstrates several important blockchain development concepts for the BSC ecosystem:

• 🎲 Provably Fair System: Implements cryptographic commitment scheme for verifiable randomness
• 🔗 On-Chain Inventory: Full on-chain storage and management of player inventory
• 💰 Automated Payments: Instant BNB payouts when selling items without manual intervention
• ✅ Verified Contract: Fully verified and transparent smart contract on BscScan
• 🚀 Production Ready: Live on BSC Mainnet with real users

Live Demo

• Website: https://www.caserush.fun
• Contract: [0x22F1e50762E8D069E18f223CDd114Ec7F586cCAD](https://bscscan.com/address/0x22F1e50762E8D069E18f223
  CDd114Ec7F586cCAD)
• GitHub: https://github.com/nangs6610/caserush

What's Included

Smart Contract (contracts/CaseRush.sol)

• Solidity 0.8.20 with optimizer enabled
• 7 unique items with weighted probabilities
• ReentrancyGuard for security
• Pausable emergency controls
• Gas-optimized storage patterns

Documentation

• Comprehensive README with setup instructions
• Smart contract deployment guide
• Economics breakdown (62.7% RTP, house edge calculation)
• Security features documentation

Tech Stack

• Backend: Solidity, Hardhat
• Frontend: Next.js 16.0, TypeScript, Tailwind CSS
• Wallet: Privy integration
• Blockchain: BSC Mainnet

Why This Example is Valuable

1. Gaming + DeFi: Shows how to combine gaming mechanics with DeFi concepts
2. Provable Fairness: Educational resource for implementing cryptographic fairness
3. On-Chain State: Demonstrates proper on-chain inventory management
4. Production Example: Not just a tutorial - this is live on mainnet with real users
5. Full Stack: Complete dApp from smart contract to UI

Developer Learning Outcomes

Developers can learn:

• How to implement provably fair randomness
• On-chain inventory and state management
• Automated cryptocurrency payouts
• Contract verification best practices
• Full-stack dApp architecture on BSC
• Wallet integration with Privy
• Gas optimization techniques

Test Plan

• ✅ Smart contract deployed and verified on BSC Mainnet
• ✅ Website live and functional at www.caserush.fun
• ✅ README documentation complete
• ✅ Contract code included in typescript/caserush/
• ✅ web/list.json updated with metadata
• ✅ Main README.md updated with example entry

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Live Production Testing

• Deployed Contract: [0x22F1e50762E8D069E18f223CDd114Ec7F586cCAD](https://bscscan.com/address/0x22F1e50762E8D0
  69E18f223CDd114Ec7F586cCAD) on BSC Mainnet
• Live Website: www.caserush.fun
• Contract Verification: Successfully verified on BscScan with public source code

Smart Contract Testing

1. Deployment: Contract successfully deployed to BSC Mainnet (Chain ID: 56)
2. Case Opening: Tested opening cases with real BNB transactions
3. Inventory Management: Verified on-chain inventory tracking works correctly
4. Sell Functionality: Confirmed automated BNB payouts work (see internal transactions on BscScan)
5. Gas Optimization: Contract optimized with 200 runs, functioning efficiently

Frontend Testing

1. Wallet Integration: Tested with Privy wallet connection (MetaMask, WalletConnect)
2. Case Opening Flow: Full user flow from wallet connection → case opening → receiving items
3. Inventory Display: Items correctly displayed from on-chain data
4. Sell Items: Sell functionality tested with real transactions
5. Responsive Design: Tested on desktop and mobile devices

To test this example:

1. Clone the example:

   git clone https://github.com/nangs6610/example-hub.git
   cd example-hub/typescript/caserush
   

2. Install dependencies:
   npm install
3. Set up environment (create .env.local):
   NEXT_PUBLIC_PRIVY_APP_ID=your_privy_app_id
   NEXT_PUBLIC_CHAIN_ID=56
   NEXT_PUBLIC_RPC_URL=https://bsc-dataseed.binance.org/
   NEXT_PUBLIC_CONTRACT_ADDRESS=0x22F1e50762E8D069E18f223CDd114Ec7F586cCAD
4. Run development server:
   npm run dev
5. Test the live contract:
   - Visit http://localhost:3000
   - Connect your BSC wallet with testnet BNB
   - Open a case (costs 0.002 BNB)
   - View inventory and test sell functionality

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[0xlucasliao]

Hey there thank you for submission we noticed that this solidity contract belongs to one of your existing projects I thought it was amazing the entire project that you were building was pretty incredible. However for the cookbook challenge we want to ensure that it is a very clear single use case of a certain example. Instead of pasting your entire solidity contract maybe you could illustrate a specific path that you want to demonstrate in your example and remove all unrelated functions.