Add first-class render examples validation target

[RayLi-Muye]

Scope

Closes #29.

• Add make render-examples as a first-class Makefile entry that invokes scripts/render-examples.sh.
• Update README and development docs so the rendered-example validation path is discoverable next to the other local validation commands.
• Add the Makefile-backed rendered example validation claim to the evidence map.

Acceptance Criteria

• make render-examples exists and runs the current rendered example validation script.
• README and development docs reference the new target consistently.
• Existing validation commands still work.
• The change stays limited to local validation ergonomics and documentation.

Validation

Local validation with Helm v3.18.6 and kubeconform v0.8.0, installed under /tmp/codex-renderfarm-tools after verifying Darwin arm64 release checksums:

• make lint
• make template
• make template-local
• make template-minio
• make template-security
• make render-examples
• make test
• make smoke-local
• git diff --check
• python3 /Users/winnie/.codex/skills/autoreview/scripts/autoreview --mode local

make render-examples rendered default, local, local MinIO, AWS GPU/SQS, and security-hardening examples and kubeconform reported all manifests valid.

Docs Impact

• README quick start and local development validation commands now use make render-examples.
• docs/development.md documents the Makefile wrapper.
• docs/evidence-map.md includes rendered example validation evidence.

Risk / Rollback

Risk is low because this wraps an existing script and does not change chart runtime behavior, rendered manifests, values, CI, cloud resources, or deployment flow. Roll back by reverting this PR if the target name or command grouping is confusing.

Security / Operations Boundary

No release, tag, package publish, deploy, live Kubernetes cluster, AWS/EKS/SQS/S3/Karpenter/IAM/Secrets Manager operation, production values, credentials, or destructive git operation was performed.