feat(aws-serverless): Add Amazon API gateway skill

[giedri]

Adding Amazon API Gateway skill (api-gateway) to aws-serverless plugin

Related

N/A

Changes

New skill — api-gateway (16 reference files):

• requirements-gathering.md — structured requirements workflow, question-driven API design process
• architecture-patterns.md — topology patterns, multi-tenant SaaS, hybrid workloads, private APIs, multi-region, streaming
• authentication.md — auth decision tree, Lambda authorizers, JWT authorizers, Cognito, IAM auth
• security.md — TLS policies, mTLS, resource policies, WAF, HttpOnly cookies, CRL checks
• custom-domains-routing.md — custom domain setup by endpoint type, base path mappings, routing rules, header-based versioning
• service-integrations.md — direct AWS service integrations without Lambda, VTL mapping templates, REST and WebSocket integration approaches
• sam-cloudformation.md — SAM/CloudFormation IaC patterns, OpenAPI extensions, VTL reference, binary data
• sam-service-integrations.md — SAM templates for EventBridge, SQS, DynamoDB CRUD, Kinesis, Step Functions integrations
• websocket.md — route selection, @connections management, session management, client resilience, SAM templates, limits
• performance-scaling.md — throttling, caching, edge caching, scaling considerations
• observability.md — logging, access log formats, enhanced observability variables, CloudWatch alarms, log retention
• deployment.md — deployment strategies, canary deployments, blue/green, routing rules
• governance.md — preventative controls (SCPs, IAM), proactive controls (CloudFormation Hooks), detective controls (Config, EventBridge)
• pitfalls.md — additional gotchas beyond SKILL.md: header handling, URL encoding, caching charges, canary deployments, usage plans
• troubleshooting.md — error diagnosis, status code resolution steps, general debugging approach
• service-limits.md — default quotas for REST, HTTP, and WebSocket APIs, adjustability notes

Acknowledgment

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