Two small corrections to the organization **Usage** page credits
display.
### 1. Label the credits panel "Credits" (was "Promo credits")
The panel surfaces any credit balance, not only promo-code redemptions,
so "Promo credits" is misleading when the credits come from another
source. Renamed the heading to "Credits".
### 2. Don't show "Included usage" for Enterprise orgs
Enterprise inherits the Pro plan's `includedUsage` value, so the Usage
bar rendered an "Included usage: $50" tier marker for Enterprise
organizations. Enterprise bills against prepaid credits rather than a
per-month included-usage tier, so the marker was misleading. The
`tierLimit` marker is now suppressed for Enterprise (`plan.type ===
"enterprise"`).
Verified with `pnpm run typecheck --filter webapp`.
Matt Aitken
95307ba33c