chore(pricing): re-verify Grok 4.7 after launch discount expiry #125

Context

main now fails the date-guard in tests/test-pricing.ts because the tracked 40% Grok 4.7 launch discount has expiresOn: "2026-09-27".

This surfaced while reviewing #124. The failure is unrelated to that PR; its routing/model tests pass up to the existing pricing guard.

Current source conflict

The authoritative pricing source still presents conflicting signals after the stated expiry:

• Command Code provider/docs still describe the Grok 4.7 40% launch discount as running through September 27, 2026.
• The current Command Code model listing/model page still displays Grok 4.7 at the discounted $1.20 input / $3.60 output / $0.30 cache-read per 1M tokens rather than an unambiguous post-promo rate.

Because of that, changing MODEL_COSTS solely to make CI green would be guessing.

Desired resolution

Re-verify the currently billed post-promo Grok 4.7 rates against an authoritative Command Code source, then update together:

• MODEL_COSTS["xai/grok-4.7"]
• any long-context tier, if applicable
• TEMPORARY_PRICING
• PRICING_LAST_VERIFIED
• focused pricing expectations/tests

Until the source is unambiguous, keep the pricing failure treated as a known main maintenance blocker rather than attributing it to unrelated contributor PRs.