AutoGen agent instrumentation

You are adding Execlave (an AI agent governance platform) to an existing Python project that uses Microsoft AutoGen (pyautogen / autogen-agentchat). Do not rewrite existing agents — only attach instrumentation. Rules you MUST follow:1. Install the correct extra: `pip install 'execlave-sdk[autogen]'`. Add it to requirements.txt / pyproject.toml.2. Read `EXECLAVE_API_KEY` from environment variables. Never hardcode keys. Add it to `.env.example`.3. Create exactly ONE Execlave client per process and reuse it: `exe = Execlave(api_key=os.environ["EXECLAVE_API_KEY"])`.4. Call `instrument_autogen_agent(agent, exe, agent_id="<stable-kebab-id>")` for each agent in the conversation, BEFORE the first `generate_reply` or chat run. Import: `from execlave.integrations.autogen import instrument_autogen_agent`.5. `agent_id` is a stable kebab-case string identifying this agent in the Execlave dashboard — NOT the AutoGen agent's display name.6. `instrument_autogen_agent` is IDEMPOTENT — a `_execlave_instrumented` marker is set on the agent so calling it twice is a no-op. Do not guard it with your own check.7. Wrap the call site (`assistant.generate_reply`, `user_proxy.initiate_chat`, etc.) in try/except for `execlave.errors.PolicyBlockedError`. On block, return a structured 4xx response containing `exc.violations`. Do NOT swallow.8. Do NOT call `exe.enforce_policy` manually — the wrapper enforces on the last user message (input policies) and on each `tool_calls` / `function_call` entry in the reply (tool-allowlist policies).9. Tool calls are extracted from both the modern `tool_calls` list and the legacy `function_call` shape. You do not need to normalise the reply yourself.10. On process shutdown, call `exe.flush()`.11. JavaScript is NOT supported — AutoGen is Python-only. Deliverables:- Add the install command and env vars to the project manifest and `.env.example`.- One diff per file; do not modify unrelated agent logic. Reference: https://www.execlave.com/docs/integrations/autogenAPI reference: https://www.execlave.com/docs/sdk-reference