bug: CLI provider retries don't preserve workspace cwd #912

Problem

When a CLI provider command fails and is retried, the retry attempts run in the eval file directory instead of the workspace directory.

Reproduction

The file-changes-graders eval uses a mock_agent CLI provider with a workspace template:

workspace:
  template: ../workspace-template

execution:
  target: mock_agent  # CLI provider

First attempt correctly runs in workspace:

[cli-provider:mock_agent] cwd=/home/runner/.agentv/workspaces/37c6082d.../shared command=bash -c '...'

Retry attempts run in the eval directory:

[cli-provider:mock_agent] cwd=/home/runner/work/agentv/agentv/examples/features/file-changes-graders/evals command=bash -c '...'

Expected behavior

All retry attempts should use the same workspace cwd as the first attempt.