Bring the starter agents' Python dependency pins (pyproject.toml + uv.lock
for adk, langgraph-fastapi, langgraph-python, pydantic-ai, strands-python;
requirements.txt + docker override for crewai-crews) in line with the
showcase fleet pin standard.
Flatten langgraph-python, langgraph-js, and mcp-apps starters so
npm install && npm run dev works out of the box. Replace Turborepo
with concurrently, move apps/* to root, update Dockerfiles, READMEs,
and entrypoints. Also remove stray pnpm-lock.yaml from a2a-a2ui and
ms-agent-framework-dotnet starters.