Add Lambda Function URL evidence fixtures

[jddark62]

Summary

• adds supplemental AWS-LAMBDA-URL-* evidence gates for Lambda Function URL discovery, auth type, resource policy, caller policy, execution-role blast radius, VPC/dependency caveats, alternate event sources, and audit/change monitoring
• keeps Lambda Function URL findings outside the CIS AWS Foundations v3.0.0 denominator in a supplemental AWS service findings table
• adds calibration fixtures covering benign IAM-authenticated CloudFront/OAC-style access, unauthenticated admin URL exposure, broad caller policy, VPC-as-private false positives, alternate trigger/audit gaps, and Not Evaluable missing policy exports

Validation

• git diff --check
• verified SKILL.md frontmatter fields
• verified Markdown fence balance and ASCII-only content for changed files
• parsed all 6 YAML fixture blocks
• verified required markers for AWS-LAMBDA-URL-01 through AWS-LAMBDA-URL-09, InvokeFunctionUrl, authorization_type, function_url_auth_type, AWS_IAM, NONE, VPC, CloudTrail, Not Evaluable, aws_lambda_function_url, and AWS::Lambda::Url
• verified AWS Lambda reference links returned HTTP 200
• privacy scan passed for changed files

/claim #1477

Payment details can be coordinated privately after maintainer acceptance.