Drop --wordmark-h from CSSProperties augmentation; inline as local const #54

Background

#53 introduced types/css.d.ts module-augmenting React.CSSProperties with two custom properties: --reveal-delay and --wordmark-h.

--wordmark-h is consumed in exactly one place: components/site/Close.tsx:30-34, where it's set on a style object and then read three times in adjacent declarations (one of them inside a calc()):

```tsx
style={{
"--wordmark-h": "clamp(4.75rem, 14vw, 11.5rem)",
height: "var(--wordmark-h)",
width: "auto",
marginLeft: "calc(var(--wordmark-h) * -0.18)",
}}
```

Both producer and consumer are in the same JSX subtree — there's no CSS-side dependency. The custom property exists only to avoid repeating the clamp(...) literal three times.

Proposal

Replace the CSS-variable indirection with a local const:

```tsx
const wordmarkH = "clamp(4.75rem, 14vw, 11.5rem)";

style={{
height: wordmarkH,
width: "auto",
marginLeft: `calc(${wordmarkH} * -0.18)`,
}}
```

Then drop "--wordmark-h"?: string; from types/css.d.ts, leaving only --reveal-delay (which is the genuine cross-language bridge — set in JSX, read by [data-reveal] rules in app/globals.css).

Why

Module augmentation merges into the global CSSProperties interface used by every style={...} in the tree. Every entry there is namespace pollution payment. --reveal-delay earns it (different files, different languages); --wordmark-h doesn't.

Out of scope

The --reveal-delay augmentation stays — it's the only entry that genuinely earns its place in a global type.

Acceptance

• --wordmark-h removed from types/css.d.ts.
• Close.tsx uses a local const for the wordmark height.
• No visual regression on the Close hero (wordmark sizing identical).
• pnpm lint and pnpm build clean.