`usage.credits` reports only `remaining`, `updatedAt`, and `events`, so the
Credits meter had to invent its own denominator: it scaled the balance against
a hardcoded 1000 credits, filling for 1000 and reading full for anything above
it. The section now prints the balance on its own until the CLI reports the
matching allowance.

`formatNumber` also formatted digits by hand, so a depleted balance printed as
"0.0", four-figure balances came out as a bare digit run, and the decimal mark
ignored the locale while every other figure in the popup went through
`groupedDecimalString`. It now shares that helper and drops the fractional part
for whole balances.

Static checks cover both rules: the Credits section may not scale the balance
against a literal again, and `formatNumber` must route through
`groupedDecimalString` instead of `toFixed`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>