v0.45.1 — give the context number its own card, not badge nineteen

The context number gets its own card instead of being the second of nineteen
badges. 0.45.0 published the figure but buried it — a shields badge in a row
with MIT License, TypeScript 5 and Node ≥20.19, which are table stakes,
next to the one number nothing else in the ecosystem publishes. It now sits
directly under the install command as a card: the figure large, a reference
unit that makes it mean something (6% of a 200K context window), the
--profile trading alternative at −57%, and the line that matters — every
turn, whether or not you call a tool.

The card is generated by npm run brand:card, never drawn by hand, so it
cannot outlive the number it states; test/schema-tokens.test.ts checks both
the light and dark variants against a live measurement and fails the build if
either drifts. Light and dark ship as separate SVGs behind <picture>, because
an SVG cannot restyle itself from the host page.