Author eval suite for agent `git-ape`

## Agent

`git-ape` — source: `.github/agents/git-ape.agent.md`

## Scope

Author the eval suite at `.github/evals/agents/git-ape/`:

- [ ] `eval.yaml` — suite config (executor, model, graders)
- [ ] At least 2 positive tasks under `tasks/positive-*.yaml`
- [ ] At least 1 negative task under `tasks/negative-*.yaml`
- [ ] Entry added to `.github/evals/manifest.yaml` at `tier: expanded`

## Dependency note

`git-ape` is the orchestrator agent. Defer this suite until most sub-agent suites (`azure-requirements-gatherer`, `azure-template-generator`, `azure-resource-deployer`, `azure-iac-exporter`) are stable — regressions in this suite are easier to root-cause when each sub-agent has its own established baseline.

## Procedure

1. `/agent-bench git-ape` drafts the suite from the live `.agent.md`.
2. `waza run .github/evals/agents/git-ape/eval.yaml -v` locally.
3. `/agent-improve git-ape` to iterate on graders.
4. Open PR.
5. Mock CI runs automatically. A maintainer will dispatch a real-model run before merge.

## Acceptance

- [ ] Suite runs cleanly in `mock` executor.
- [ ] At least one positive task passes in a real-model run.
- [ ] All negative tasks produce a refusal or out-of-scope acknowledgement.
- [ ] `manifest.yaml` entry added; PR description includes the real-model run summary.

## Conventions to follow

- Persona lock: refusal graders should accept the agent's own scope language.
- Prompt graders need `continue_session: true` in their grader config.
- This agent has destructive tools through delegation. Apply the same "no real deploy" rule as `azure-resource-deployer`: positive tasks grade safety-contract behavior, not real Azure execution.

## Related

- Umbrella: #93
- Harness: #61