[Shahid-Musabbar]

##What
Adds an AutoGen adapter (autogen-agentchat >= 0.4), following the pattern of the existing adapters.

• opengap export -f autogen generates a standalone Python script.
• opengap run -a autogen generates the script and runs it with the local Python interpreter (python3, python or py). It also works through the git runner.
• With no sub-agents, the script is a single AssistantAgent.
• With sub-agents, the main agent and every entry under agents: become AssistantAgents in a SelectorGroupChat. The main agent owns the request and consults specialists. The run ends when a message contains TERMINATE or at runtime.max_turns (default 20).
• Sub-agents can be full agents (agents/<name>/agent.yaml) or lightweight ones (a description plus an optional SOUL.md). Each uses its own model if it sets one.
• Tools from tools/*.yaml become FunctionTools. The function bodies are placeholders, since tool yamls only describe the interface.
• The model client is chosen from the model name or a provider/model prefix: openai, azure, anthropic, ollama, gemini or llama. Clients are imported lazily, so only the extra for the provider in use needs installing.
• Registered in export, run and the git runner. README, docs and the package.json keywords are updated.
• Adds src/adapters/autogen.test.ts, which covers the single-agent and team output, sub-agent descriptions and souls, selector prompt placeholders, tools, model default, the prompt override and identifier sanitising.

Why

AutoGen is a widely used multi-agent framework, and gitagent's sub-agent definitions map cleanly onto SelectorGroupChat.

The selector prompt and coordinator instructions are deliberately general. The main agent is treated as the owner of the task, and sub-agents are helpers it consults, not a planner handing out assignments. Specialists are chosen by their descriptions, so a main agent that does one job and uses other agents as tools also works.

I tried this with a hotel-helpdesk agent and a reservations sub-agent. A check-in/check-out question was routed to the sub-agent instead of being answered by the main agent directly.

Note: a description under the parent's agents: map overrides the sub-agent's own agent.yaml description. This is existing behaviour that other adapters share, not something this PR changes.

Closes the Autogen part of the issue #3

How Tested

• npm run build passes
• gitagent validate passes on example agents
• Manual testing (describe below)

Added autogen.test.ts file with the tests conducted.

Checklist

• My code follows the existing style of this project
• I have added/updated tests (if applicable)
• I have updated documentation (if applicable)
• I have read the CONTRIBUTING.md