fix(resources): use next/font CSS variables, not literal font names

The audit caught a real bug: `resources.css` declared
`font-family: 'IBM Plex Mono'` and `font-family: 'Libre Baskerville'`
as literal font names. `next/font/google` does not register the loaded
webfonts under those names — it generates hashed family names and
exposes them via `--font-ibm-plex-mono` and `--font-libre-baskerville`
CSS variables on the same element that gets the `*-module__*__variable`
class.

The shipped CSS therefore never used the downloaded webfonts; visitors
without the fonts installed locally saw the generic monospace / Georgia
fallback chain instead of the intended typography.

Switched all four font-family declarations to reference the variables
first, then the literal name, then a generic family:

  font-family: var(--font-ibm-plex-mono), 'IBM Plex Mono', ui-monospace, ...
  font-family: var(--font-libre-baskerville), 'Libre Baskerville', Georgia, serif

Also fixed the Wordmark SVG which had a hardcoded `fontFamily` SVG
attribute (overrides CSS); replaced with an inline `style` referencing
the same CSS variable.

Verified the CSS bundle now contains var(--font-ibm-plex-mono) and
var(--font-libre-baskerville) at the relevant rules.

components/resources/icons.tsx

@@ -15,10 +15,13 @@ export function Wordmark(props: IconProps) {
       className="wordmark"
       {...props}
     >
+      {/* font-family pulls from the parent's CSS, which is the next/font
+        * variable set by `(resources)/layout.tsx`. Falls back through
+        * system mono if for any reason the var is unset. */}
       <text
         x="0"
         y="34"
-        fontFamily="'IBM Plex Mono', monospace"
+        style={{ fontFamily: 'var(--font-ibm-plex-mono), "IBM Plex Mono", ui-monospace, monospace' }}
         fontSize="28"
         fontWeight="500"
         fill="currentColor"