feat(branding): self-hosted webfonts with filesystem scanner

frontend/src/services/fonts.service.ts

@@ -0,0 +1,55 @@
+import { api } from '../config/api';
+
+export interface FontDefinition {
+  family: string;
+  weights: number[];
+}
+
+export interface FontsListResponse {
+  fonts: FontDefinition[];
+}
+
+export const fontsService = {
+  /**
+   * List all self-hosted font families discovered by the backend scanner.
+   * Cached aggressively at the React Query layer; the underlying endpoint
+   * is also TTL-cached on the backend.
+   */
+  async list(): Promise<FontDefinition[]> {
+    const res = await api.get<FontsListResponse>('/public/fonts');
+    return res.data.fonts;
+  }
+};
+
+const GENERIC_FAMILIES = new Set([
+  'sans-serif',
+  'serif',
+  'monospace',
+  'cursive',
+  'fantasy',
+  'system-ui',
+  'ui-sans-serif',
+  'ui-serif',
+  'ui-monospace',
+  'ui-rounded'
+]);
+
+/**
+ * Extract the primary font family name from a CSS font-family string.
+ *
+ * "'Jost', sans-serif"            → "Jost"
+ * "Inter, sans-serif"             → "Inter"
+ * "'Playfair Display', serif"     → "Playfair Display"
+ * "system-ui, sans-serif"         → null   (generic, no @font-face needed)
+ * undefined / "" / "sans-serif"   → null
+ */
+export function extractFamilyName(cssFontFamily: string | undefined | null): string | null {
+  if (!cssFontFamily) return null;
+  const first = cssFontFamily.split(',')[0]?.trim();
+  if (!first) return null;
+  // Strip surrounding single or double quotes
+  const unquoted = first.replace(/^['"]|['"]$/g, '').trim();
+  if (!unquoted) return null;
+  if (GENERIC_FAMILIES.has(unquoted.toLowerCase())) return null;
+  return unquoted;
+}