Python: drop a console script whose callable does not exist - #10169

Motivation & Context

python/packages/lab/pyproject.toml declares two console scripts:

[project.scripts]
gaia_viewer = "agent_framework_lab_gaia:viewer_main"
lightning = "agent_framework_lab_lightning:main"

The lightning target does not exist. lightning/agent_framework_lab_lightning/__init__.py defines one public name, AgentFrameworkTracer (__all__ = ["AgentFrameworkTracer"]), so installing agent-framework-lab[lightning] produces a lightning executable that fails on import instead of running. The two main() functions in the package live in lightning/samples/train_tau2_agent.py and lightning/samples/train_math_agent.py; neither is importable as agent_framework_lab_lightning:main.

The sibling entry is fine: viewer_main is defined in gaia/agent_framework_lab_gaia/ and re-exported from its __init__.py (line 8, listed in __all__ on line 25).

Description & Review Guide

• What are the major changes? Deletes one line: the lightning console script. Nothing else moves — no import, no package, no __init__.
• What is the impact of these changes? pip install "agent-framework-lab[lightning]" no longer advertises a command that cannot start. The lightning extra and the agent_framework_lab_lightning package itself are untouched; library users import AgentFrameworkTracer exactly as before.
• What do you want reviewers to focus on? Whether a lightning CLI is planned. If it is, the fix should be a real main() in agent_framework_lab_lightning rather than removing the entry — say so and I will implement it instead. A command that raises ImportError the first time a user types it is the worse of the two states, which is why this PR takes the removal path.

Evidence gathered before touching anything (run on the parent commit):

$ python - <<'PY'
import ast, tomllib, pathlib
py = tomllib.loads(pathlib.Path("python/packages/lab/pyproject.toml").read_text())
pkg = pathlib.Path("python/packages/lab/lightning/agent_framework_lab_lightning/__init__.py")
names = {n.name for n in ast.parse(pkg.read_text()).body
         if isinstance(n, (ast.FunctionDef, ast.AsyncFunctionDef, ast.ClassDef))}
print(py["project"]["scripts"])                       # {... , 'lightning': 'agent_framework_lab_lightning:main'}
print("main" in names)                                # False
PY
$ grep -rn "def main" python/packages/lab/lightning/agent_framework_lab_lightning/
(no matches; the only main() functions are under lightning/samples/, which has no __init__.py
 and is not listed in [tool.setuptools] packages)
$ grep -rn "lightning" .github/workflows/*.yml
(no CI job invokes the command)

Related Issue

N/A - trivial change. One deleted line, no design decision, and the alternative (implementing the CLI) is called out above rather than silently chosen.

AI Assistance

• This is an AI-assisted contribution. I reviewed, understood, and verified all submitted content and accept responsibility for it.

AI assistance details: the console-script target was found with a static check that resolves module:attr entries in pyproject.toml against the modules' top-level bindings; the absence of main, the sibling script's validity, and the lack of any workflow or docs reference were then confirmed by hand with the commands above. The description was written from those results.

Contribution Checklist

• The code builds clean without any errors or warnings — the file parses (tomllib.load) and the resulting [project.scripts] is {'gaia_viewer': ...}.
• All unit tests pass, and I have added new tests where possible — no test added: packaging metadata only, and no test exercises the console script.
• The PR follows the Contribution Guidelines.
• This PR links to an agreed issue with no competing open PR, or the Related Issue section documents a trivial-change exception.
• This is not a breaking change — the deleted command never worked.