feat(web): wire Tailwind fontFamily to FS font tokens

Removes duplication between fabledsword-tokens.css and tailwind.config.js;
font stacks now live in one place so per-app overrides reach Tailwind utilities.

web/tailwind.config.js

@@ -34,9 +34,9 @@ export default {
         xl: 'var(--fs-radius-xl)'
       },
       fontFamily: {
-        display: ['Fraunces', 'Georgia', 'serif'],
+        display: ['var(--fs-font-display)'],
-        sans: ['Inter', 'system-ui', 'sans-serif'],
+        sans: ['var(--fs-font-body)'],
-        mono: ['JetBrains Mono', 'ui-monospace', 'monospace']
+        mono: ['var(--fs-font-mono)']
       }
     }
   },