Add lower-corner layouts, custom blur backgrounds, and classic blur fill.

Ship composition families, optional background images for lower-corner templates, and an optional blurred cover fill for classic letterbox.

lib/fonts.ts

@@ -3,6 +3,15 @@
 /** Max custom font upload size (10 MB). */
 export const FONT_UPLOAD_MAX_BYTES = 10 * 1024 * 1024;
 
+/** Bundled default font for preview + FFmpeg parity (Apache 2.0, Google Arimo). */
+export const SYSTEM_FONT = {
+  key: "system",
+  label: "Arimo",
+  file: "Arimo-Regular.ttf",
+  boldFile: "Arimo-Bold.ttf",
+  previewFamily: "S2VIDPreview-system",
+} as const;
+
 export const CURATED_FONTS = [
   {
     key: "inter",
@@ -10,6 +19,7 @@ export const CURATED_FONTS = [
     cssFamily: "Inter",
     googleCss: "Inter:wght@400;600",
     file: "Inter-Regular.ttf",
+    boldFile: null as string | null,
   },
   {
     key: "montserrat",
@@ -17,6 +27,7 @@ export const CURATED_FONTS = [
     cssFamily: "Montserrat",
     googleCss: "Montserrat:wght@400;600",
     file: "Montserrat-Regular.ttf",
+    boldFile: null as string | null,
   },
   {
     key: "roboto",
@@ -24,6 +35,7 @@ export const CURATED_FONTS = [
     cssFamily: "Roboto",
     googleCss: "Roboto:wght@400;500",
     file: "Roboto-Regular.ttf",
+    boldFile: null as string | null,
   },
   {
     key: "oswald",
@@ -31,6 +43,7 @@ export const CURATED_FONTS = [
     cssFamily: "Oswald",
     googleCss: "Oswald:wght@400;500",
     file: "Oswald-Regular.ttf",
+    boldFile: null as string | null,
   },
   {
     key: "playfair",
@@ -38,6 +51,7 @@ export const CURATED_FONTS = [
     cssFamily: "Playfair Display",
     googleCss: "Playfair+Display:wght@400;600",
     file: "PlayfairDisplay-Regular.ttf",
+    boldFile: null as string | null,
   },
 ] as const;