Add provider usage discovery evaluation

[Copilot]

The issue proposes auto-discovering configured AI providers on the Hermes host and surfacing current token/credit usage in a Liquid Glass modal like the supplied app mockup.

• Evaluation

  • Added docs/PROVIDER_USAGE_EVALUATION.md with an initial technical read of the request.
  • Scored feasibility at 2/5 and expected UX value at 4/5.

• Recommendation

  • Documents a No Build recommendation for the full feature in this repository until provider-specific usage sources, authorization, and safe Link payload contracts are defined.
  • Calls out that the plugin can support safe host-side discovery, while the native Liquid Glass modal belongs in the app surface.

• Fixes Auto discover current providers and display usage in app #3