feat(earthen): bundle Fraunces + Work Sans via @font-face + preset typography refs

Host BundledFonts is inert, so declare the two fonts.json families as
@font-face against /templates/earthen/fonts/*.woff2 and point every preset's
typography.fontHeading/fontBody at template:earthen:<Family> so --font-heading
and --font-body resolve to the bundled faces.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

manifest.yaml

@@ -113,7 +113,18 @@ css:
     /* Earthen — theme utilities injected via CSSManifest.InputCSSAppend. */
     /* All colour values reference the 19-token HSL custom properties so they */
     /* shift with the active preset (mossbed, clay-field, wet-loam). */
-    
+
+    /* Bundled faces. The host does not yet emit @font-face for fonts.json
+     * (LoadedPlugin.BundledFonts is inert), so the theme declares them itself
+     * against the served /templates/earthen/fonts/... paths. Presets set
+     * typography.fontHeading/body to template:earthen:<Family> so
+     * --font-heading/--font-body resolve to these families. Families/weights
+     * match fonts.json exactly. */
+    @font-face { font-family: 'Fraunces'; src: url('/templates/earthen/fonts/fraunces-latin-400.woff2') format('woff2'); font-weight: 400; font-style: normal; font-display: swap; }
+    @font-face { font-family: 'Fraunces'; src: url('/templates/earthen/fonts/fraunces-latin-600.woff2') format('woff2'); font-weight: 600; font-style: normal; font-display: swap; }
+    @font-face { font-family: 'Work Sans'; src: url('/templates/earthen/fonts/worksans-latin-400.woff2') format('woff2'); font-weight: 400; font-style: normal; font-display: swap; }
+    @font-face { font-family: 'Work Sans'; src: url('/templates/earthen/fonts/worksans-latin-600.woff2') format('woff2'); font-weight: 600; font-style: normal; font-display: swap; }
+
     /* Paper grain backdrop — a single inline SVG noise pattern keeps page weight
        inside the marketplace gate (≤ 81920 bytes). */
     .bg-paper-grain {

presets.json

@@ -5,6 +5,10 @@
     "description": "Cream paper, deep moss primary, terracotta accent — the canonical Earthen look.",
     "theme": {
       "mode": "both",
+      "typography": {
+        "fontHeading": "template:earthen:Fraunces",
+        "fontBody": "template:earthen:Work Sans"
+      },
       "lightColors": {
         "background": "40 30% 96%",
         "foreground": "120 25% 14%",
@@ -55,6 +59,10 @@
     "description": "Warm terracotta-led palette tuned for farm-stand and outdoor-brand sites.",
     "theme": {
       "mode": "light",
+      "typography": {
+        "fontHeading": "template:earthen:Fraunces",
+        "fontBody": "template:earthen:Work Sans"
+      },
       "lightColors": {
         "background": "30 35% 95%",
         "foreground": "20 35% 16%",
@@ -84,6 +92,10 @@
     "description": "Deep night-soil tones for conservation orgs that need quiet authority.",
     "theme": {
       "mode": "dark",
+      "typography": {
+        "fontHeading": "template:earthen:Fraunces",
+        "fontBody": "template:earthen:Work Sans"
+      },
       "darkColors": {
         "background": "90 20% 6%",
         "foreground": "60 20% 90%",
@@ -113,6 +125,10 @@
     "description": "Pale sage paper and honey light, misty forest dark — a softer, hopeful reading of the palette.",
     "theme": {
       "mode": "both",
+      "typography": {
+        "fontHeading": "template:earthen:Fraunces",
+        "fontBody": "template:earthen:Work Sans"
+      },
       "lightColors": {
         "background": "70 25% 95%",
         "foreground": "130 20% 16%",
@@ -163,6 +179,10 @@
     "description": "Terracotta-led warm clay in light, firelight ember over deep loam in dark — moss becomes the accent.",
     "theme": {
       "mode": "both",
+      "typography": {
+        "fontHeading": "template:earthen:Fraunces",
+        "fontBody": "template:earthen:Work Sans"
+      },
       "lightColors": {
         "background": "28 38% 95%",
         "foreground": "18 40% 15%",