Feature Suggestion: Optional token metering & paid API key support via `neuforge-pay`

Hi @google-gemini,

Love the work on `google-gemini/gemini-cli`! As usage grows across AI agent frameworks, server compute costs can start adding up quickly.

Would you be open to adding an optional usage metering & billing decorator using `neuforge-pay`? It allows developers hosting instance deployments of your MCP server to automatically meter tokens, track real-time LLM COGS, and attach paid Stripe keys in 3 lines of code.

Example Integration:
```python
from neuforge_pay import meter_endpoint

@app.get("/v1/query")
@meter_endpoint(price_charged_usd=0.05, model_name="claude-3-5-sonnet")
async def query_endpoint():
...
```

Happy to submit a clean PR if this aligns with your roadmap!

No repository files or tests are named. Start by reviewing the gemini-cli MCP server and any `/v1/query` entry point to determine whether instance deployments support the proposed integration; then establish the project’s position on optional token metering, billing, and paid API keys. Done would require an agreed scope and implementation path for `neuforge-pay` support.

Written by the indexing model from the issue text.