Address adversarial review findings

- evals/README.md, evals/CLAUDE.md: fix uv install command from
  'uv sync --dev' to 'uv sync --extra dev'. Drill's pyproject.toml
  uses [project.optional-dependencies], so --dev is a no-op for
  pytest/ruff/ty; --extra dev is the correct invocation.
- tests/claude-code/run-skill-tests.sh: drop test-requesting-code-review.sh
  from integration_tests array (file deleted earlier in this branch).
- tests/claude-code/README.md: replace test-requesting-code-review.sh
  section with test-worktree-native-preference.sh (the worktree test
  is kept; the code-review test was lifted into drill).
- docs/testing.md, CLAUDE.md: remove "Copilot CLI" from the harness
  list. evals/backends/ has claude*, codex, gemini configs but no
  copilot.yaml, so the claim was unsupported.

Adversarial review credit: reviewer #2 found four legitimate issues
(uv-sync, run-skill-tests stale ref, README stale ref via #1, and
Copilot CLI fabrication); reviewer #1 found two distinct issues
(run-skill-tests + tests/claude-code/README.md). Reviewer #2 wins
this round.

evals/CLAUDE.md

@@ -4,7 +4,7 @@ Superpowers skill compliance benchmark. Python 3.11+, managed with uv.
 
 ## Commands
 
-- **install**: `uv sync --dev`
+- **install**: `uv sync --extra dev`
 - **test**: `uv run pytest`
 - **test single**: `uv run pytest tests/test_engine.py -x -q`
 - **lint**: `uv run ruff check`

evals/README.md

@@ -15,7 +15,7 @@ correctly.
 ## Setup
 
 ```bash
-uv sync --dev
+uv sync --extra dev
 ```
 
 Required environment: