Consolidate crewai run and crewai flow kickoff (#6296)

Make `crewai run` the single execution path for crews and flows, with
`crewai flow kickoff` kept as a deprecated compatibility alias.

lib/cli/tests/test_create_flow.py

@@ -28,9 +28,7 @@ def test_create_flow_declarative_project_can_run(
     assert (project_root / pyproject["tool"]["crewai"]["definition"]).is_file()
 
     monkeypatch.chdir(project_root)
-    result = CliRunner().invoke(
-        crewai, ["flow", "kickoff"], env={"UV_RUN_RECURSION_DEPTH": "1"}
-    )
+    result = CliRunner().invoke(crewai, ["run"], env={"UV_RUN_RECURSION_DEPTH": "1"})
 
     assert result.exit_code == 0
     assert "Running the Flow" in result.output