fix: add test dependencies to cogames release workflow (#5968)

- Add test optional dependency group to cogames pyproject.toml
- Install cogames with [test,agents] extras in CI to fix:
  - Missing ruff binary (19 test failures in docsync tests)
  - Missing cogames_agents module (2 test failures in scripted policy tests)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: yatharth

pyproject.toml

@@ -35,6 +35,7 @@ dynamic = ["version"]
 
 [project.optional-dependencies]
 agents = ["cogames-agents>=0.0.1"]
+test = ["pytest", "pytest-xdist", "ruff", "cogames-agents>=0.0.1"]
 
 [project.scripts]
 cogames = "cogames.main:app"