Add xlayer-expert AI coding skill to toolkit

[cberktavsan]

Summary

• Adds xlayer-expert as a new tool under tools/xlayer-expert/ — an AI coding assistant skill that provides deep expertise for building on X Layer
• Updates the main README.md to include xlayer-expert in the Modules section

What is xlayer-expert?

An AI coding assistant skill that gives coding tools (Claude Code, Cursor, Windsurf, Codex CLI, Gemini CLI) specialized knowledge about X Layer development:

• 22 Security Golden Rules for Solidity smart contracts
• Network configuration — RPC endpoints, chain IDs (196/1952), re-genesis block
• Deployment patterns — Hardhat & Foundry config, proxy/upgrade (UUPS), contract verification
• Gas optimization — OKB economics, L1 data fees, storage packing
• Bridge & cross-chain — OP Stack predeploys, L2→L1 withdrawals
• OKLink OnChain Data API — HMAC auth, block/tx/token queries

Source repository: cberktavsan/xlayer-expert

New Files

tools/xlayer-expert/
├── SKILL.md                  # Main skill file with Golden Rules and triggers
├── README.md                 # Installation and usage guide
├── LICENSE                   # MIT License
└── references/
    ├── security.md           # Solidity security rules, L2 risks
    ├── contract-patterns.md  # Hardhat/Foundry config, deploy, verify
    ├── gas-optimization.md   # OKB fee structure, optimization
    ├── network-config.md     # RPC URLs, chain IDs
    ├── token-addresses.md    # Token addresses + Multicall3
    ├── l2-predeploys.md      # OP Stack predeploy addresses
    ├── testing-patterns.md   # Forking, security testing
    ├── flashblocks.md        # Flashblocks API, reorg risks
    ├── infrastructure.md     # RPC providers, monitoring
    ├── onchain-data-api.md   # OKLink REST API
    └── zkevm-differences.md  # CDK to OP Stack migration

Test plan

• Verify skill installs correctly via cp to ~/.claude/skills/
• Verify npx skills add berktavsan/xlayer-expert works
• Check all reference file links are valid

🤖 Generated with Claude Code

need to review again