feat: add WAFv2 Web ACL browser

[YoungJinJung]

Summary

Add a read-only AWS WAFv2 Web ACL browser for regional and CloudFront protection posture.

Details

• List regional Web ACLs in the active region and CloudFront-scope Web ACLs through the required us-east-1 endpoint.
• Show default action, capacity, managed/custom rules, priorities, override actions, visibility configuration, and logging status.
• List protected resources associated with each Web ACL where the API supports it.
• Highlight ACLs without logging, with permissive default actions, or with no associated resources as informational posture signals.
• Keep regional and CloudFront failures isolated so one scope remains usable when the other is denied.
• Initial scope is read-only; rule updates, IP-set changes, and association mutations are excluded.
• AWS API reference: https://docs.aws.amazon.com/waf/latest/APIReference/API_GetWebACL.html

Checklist

• Add WAF service and feature identifiers in internal/domain/model.go and internal/domain/catalog.go
• Add Web ACL, rule, association, and logging models under internal/services/aws/
• Add mockable WAFv2 clients for regional and CloudFront scopes in internal/services/aws/repository.go
• Add ACL list and scrollable rule/detail screens under internal/app/
• Cover pagination, scope routing, partial failures, deterministic rule ordering, and compact terminals
• Add mock-client tests following existing AWS service patterns
• Update README.md and docs/service-specific-highlights.md
• Run make test and make build

[YoungJinJung]

@Unic-bot: assign me

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@YoungJinJung has been assigned to this issue.