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/payment-processing/skills/pci-compliance/SKILL.md

@@ -446,35 +446,3 @@ PCI_COMPLIANCE_CHECKLIST = {
     ]
 }
 ```
-
-## Resources
-
-- **references/data-minimization.md**: Never store prohibited data
-- **references/tokenization.md**: Tokenization strategies
-- **references/encryption.md**: Encryption requirements
-- **references/access-control.md**: Role-based access
-- **references/audit-logging.md**: Comprehensive logging
-- **assets/pci-compliance-checklist.md**: Complete checklist
-- **assets/encrypted-storage.py**: Encryption utilities
-- **scripts/audit-payment-system.sh**: Compliance audit script
-
-## Common Violations
-
-1. **Storing CVV**: Never store card verification codes
-2. **Unencrypted PAN**: Card numbers must be encrypted at rest
-3. **Weak Encryption**: Use AES-256 or equivalent
-4. **No Access Controls**: Restrict who can access cardholder data
-5. **Missing Audit Logs**: Must log all access to payment data
-6. **Insecure Transmission**: Always use TLS 1.2+
-7. **Default Passwords**: Change all default credentials
-8. **No Security Testing**: Regular penetration testing required
-
-## Reducing PCI Scope
-
-1. **Use Hosted Payments**: Stripe Checkout, PayPal, etc.
-2. **Tokenization**: Replace card data with tokens
-3. **Network Segmentation**: Isolate cardholder data environment
-4. **Outsource**: Use PCI-compliant payment processors
-5. **No Storage**: Never store full card details
-
-By minimizing systems that touch card data, you reduce compliance burden significantly.