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/defi-protocol-templates/SKILL.md

@@ -422,33 +422,3 @@ contract FlashLoanReceiver is IFlashLoanReceiver {
     }
 }
 ```
-
-## Resources
-
-- **references/staking.md**: Staking mechanics and reward distribution
-- **references/liquidity-pools.md**: AMM mathematics and pricing
-- **references/governance-tokens.md**: Governance and voting systems
-- **references/lending-protocols.md**: Lending/borrowing implementation
-- **references/flash-loans.md**: Flash loan security and use cases
-- **assets/staking-contract.sol**: Production staking template
-- **assets/amm-contract.sol**: Full AMM implementation
-- **assets/governance-token.sol**: Governance system
-- **assets/lending-protocol.sol**: Lending platform template
-
-## Best Practices
-
-1. **Use Established Libraries**: OpenZeppelin, Solmate
-2. **Test Thoroughly**: Unit tests, integration tests, fuzzing
-3. **Audit Before Launch**: Professional security audits
-4. **Start Simple**: MVP first, add features incrementally
-5. **Monitor**: Track contract health and user activity
-6. **Upgradability**: Consider proxy patterns for upgrades
-7. **Emergency Controls**: Pause mechanisms for critical issues
-
-## Common DeFi Patterns
-
-- **Time-Weighted Average Price (TWAP)**: Price oracle resistance
-- **Liquidity Mining**: Incentivize liquidity provision
-- **Vesting**: Lock tokens with gradual release
-- **Multisig**: Require multiple signatures for critical operations
-- **Timelocks**: Delay execution of governance decisions