fix(skills): remove phantom resource references and fix CoC links (#447)

Remove references to non-existent resource files (references/, assets/,
scripts/, examples/) from 115 skill SKILL.md files. These sections
pointed to directories and files that were never created, causing
confusion when users install skills.

Also fix broken Code of Conduct links in issue templates to use
absolute GitHub URLs instead of relative paths that 404.

plugins/blockchain-web3/skills/web3-testing/SKILL.md

@@ -388,28 +388,3 @@ jobs:
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v2
 ```
-
-## Resources
-
-- **references/hardhat-setup.md**: Hardhat configuration guide
-- **references/foundry-setup.md**: Foundry testing framework
-- **references/test-patterns.md**: Testing best practices
-- **references/mainnet-forking.md**: Fork testing strategies
-- **references/contract-verification.md**: Etherscan verification
-- **assets/hardhat-config.js**: Complete Hardhat configuration
-- **assets/test-suite.js**: Comprehensive test examples
-- **assets/foundry.toml**: Foundry configuration
-- **scripts/test-contract.sh**: Automated testing script
-
-## Best Practices
-
-1. **Test Coverage**: Aim for >90% coverage
-2. **Edge Cases**: Test boundary conditions
-3. **Gas Limits**: Verify functions don't hit block gas limit
-4. **Reentrancy**: Test for reentrancy vulnerabilities
-5. **Access Control**: Test unauthorized access attempts
-6. **Events**: Verify event emissions
-7. **Fixtures**: Use fixtures to avoid code duplication
-8. **Mainnet Fork**: Test with real contracts
-9. **Fuzzing**: Use property-based testing
-10. **CI/CD**: Automate testing on every commit