Add chart contract tests and schema coverage

[RayLi-Muye]

Scope

Closes #3.

• Add local chart contract tests for default, local, and AWS GPU/SQS rendering paths.
• Add negative schema checks for invalid replicaCount, GPU count, worker image pull policy, and postprocess image pull policy.
• Extend values schema coverage for KEDA trigger fields and postprocess job image/name fields.
• Run the new contract tests in GitHub Actions and expose them through make test.
• Update development docs, evidence map, and delivery prompts.

Acceptance Criteria

• Tests cover GPU enabled/disabled rendering.
• Tests cover KEDA enabled/disabled rendering.
• Schema rejects invalid replica counts, GPU counts, and image pull policies.
• GitHub Actions runs the new checks on PRs.

Validation

• PATH=/tmp/codex-renderfarm-tools/bin:$PATH make test
• make smoke-local
• bash -n scripts/chart-contract-tests.sh
• PATH=/tmp/codex-renderfarm-tools/bin:$PATH make lint
• PATH=/tmp/codex-renderfarm-tools/bin:$PATH make template >/tmp/renderfarm-template-aws.yaml
• PATH=/tmp/codex-renderfarm-tools/bin:$PATH make template-local >/tmp/renderfarm-template-local.yaml
• PATH=/tmp/codex-renderfarm-tools/bin:$PATH scripts/render-examples.sh
• python3 -m json.tool charts/render-worker/values.schema.json >/tmp/render-worker-values.schema.json
• git diff --check
• python3 /Users/winnie/.codex/skills/autoreview/scripts/autoreview --mode branch --base origin/main

render-examples.sh validated default, local, and AWS GPU/SQS rendered manifests with kubeconform strict.

Docs Impact

• Development docs list make test.
• Evidence map adds chart contract tests and updates the CI claim.
• Delivery prompts mark the Add chart unit tests and stronger values schema #3 node as implemented and identify possible follow-up depth.

Risk / Rollback

Risk is low: this adds local/CI validation and schema checks without changing rendered manifests for current default, local, or AWS examples. Rollback is reverting this commit to remove the test script, CI step, schema additions, and docs updates.

Security Notes

No cloud credentials, production resources, renderer binaries, license files, customer assets, or account-specific values are included.