fix(evals): resolve tool paths from BASE cwd

[svozza]

Summary

• grade relative read-only tool paths against the BASE cwd configured by cc_loop
• treat pathless Grep and Glob requests as searches of that fixed cwd
• keep rejecting explicit PR-head paths, sibling-prefix paths, and traversal outside BASE
• add a deterministic regression for PR refactor: use direct standard JSON schemas #76 attempt 1's pathless Grep followed by an absolute BASE Read

Why

PR #76 run 32378471020 attempt 1 found the line-12 slice_dictionary defect, searched from the real BASE cwd, read the pinned parameters/ssm.py caller, and submitted the correct SSM impact. The eval nevertheless failed because its Grep request omitted an explicit BASE path.

That is stricter than production. cc_loop fixes the CLI cwd to BASE and exposes no tool that can change it, so pathless Grep/Glob and relative paths have a deterministic location. The existing grader discarded that known execution context and produced a false behavioral failure.

This changes the grader, not expect.json: the scenario still requires investigation of both slice_dictionary and parameters/ssm.py under BASE.

Verification

• uv lock --check
• uv sync --frozen --all-groups --no-install-project --check
• uv run --frozen --group test python -m pytest tests/test_run_evals.py -p no:cacheprovider -q (380 passed, 2 skipped)
• uv run --frozen --group test python -m pytest tests/ -p no:cacheprovider -q (2301 passed, 2 skipped)
• uv run --frozen --group typecheck ty check --python .venv/bin/python

A direct branch workflow dispatch was attempted as run 32382298342, but the eval job was rejected before starting because the runtime environment intentionally allows only main. The PR-triggered pull_request_target workflow is the supported credentialed path for executing PR-head eval code.

[svozza]

Final verification on PR head af5746c:

• Quality check: test_verifier passed; typecheck passed
• Protected eval run 32382365886: 42/42 review scenarios passed, including caller_impact_needs_investigation; 0 behavioral failures; 0 invalid samples
• Plan evals: 6/6 passed

The attempted direct branch dispatch (32382298342) produced no sample because the main-only runtime environment rejected the job before steps started; the PR-triggered pull_request_target run is the supported credentialed execution path and completed successfully.