feat(book): redeploy calculator with v2 design fixes

Rebuilt from inference-field-guide wip/calculator-design-fix
(commits 8aed539 through c9a0faf):
- backtick-wrap dollar amounts (fixes KaTeX math-mode mangling)
- horizontal Compare-view bars (fixes 30+ overlapping x-axis labels)
- moss/oxblood marimo-theme.css rewrite against Marimo 0.23 DOM
- _theme_css cell returns mo.Html() for reliable CSS injection
- Google Fonts stylesheet injected into bundle for first-paint
  Newsreader (no Lora flash)

Author: Sohailm25