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/backend-development/skills/microservices-patterns/SKILL.md

@@ -562,34 +562,3 @@ async def call_payment_service(payment_data: dict):
         payment_data
     )
 ```
-
-## Resources
-
-- **references/service-decomposition-guide.md**: Breaking down monoliths
-- **references/communication-patterns.md**: Sync vs async patterns
-- **references/saga-implementation.md**: Distributed transactions
-- **assets/circuit-breaker.py**: Production circuit breaker
-- **assets/event-bus-template.py**: Kafka event bus implementation
-- **assets/api-gateway-template.py**: Complete API gateway
-
-## Best Practices
-
-1. **Service Boundaries**: Align with business capabilities
-2. **Database Per Service**: No shared databases
-3. **API Contracts**: Versioned, backward compatible
-4. **Async When Possible**: Events over direct calls
-5. **Circuit Breakers**: Fail fast on service failures
-6. **Distributed Tracing**: Track requests across services
-7. **Service Registry**: Dynamic service discovery
-8. **Health Checks**: Liveness and readiness probes
-
-## Common Pitfalls
-
-- **Distributed Monolith**: Tightly coupled services
-- **Chatty Services**: Too many inter-service calls
-- **Shared Databases**: Tight coupling through data
-- **No Circuit Breakers**: Cascade failures
-- **Synchronous Everything**: Tight coupling, poor resilience
-- **Premature Microservices**: Starting with microservices
-- **Ignoring Network Failures**: Assuming reliable network
-- **No Compensation Logic**: Can't undo failed transactions