docs: Metis decisions now count toward the allowance

Metering on /v1/systemone is live: each call is billed at $0.12 per 1M
input tokens, computed from the exact token count GreenPT returns and
attributed to the calling member key. Replace the "not yet metered"
warnings in models.md and api-access.md with the accurate position.

(metering verified 2026-11-03; code/litellm patch_passthrough_token_cost.py)

api-access.md

@@ -84,9 +84,10 @@ Two practical notes:
   and receive probabilities; there is nothing for an OpenAI SDK's
   `chat.completions` to parse. Post the body directly (`curl`, `requests`,
   `httpx`, or an SDK's generic POST).
-- **Its usage is not yet metered** (see the note in the model list): calls
-  currently register no spend against your key. Use it as though it counted
-  toward your allowance, because that is what it is meant to do.
+- **Its usage is metered like any other call.** Each decision is billed at
+  **$0.12 per 1M input tokens**, figured from the exact token count GreenPT
+  returns (Metis generates no prose, so there is no output cost). Decisions draw
+  on the same monthly allowance as chat.
 
 ## Coding agents and other OpenAI-compatible clients