Add font import for Now, Gotham and Open Sauce One overrides; package fonts for Void

Font import:
- Migration M6 adds user_fonts; files are stored content-addressed under
  the local data dir. New Rust commands inspect, import, list, read and
  remove fonts, refusing WOFF2, collections, variable fonts and
  restricted fsType, and unpacking WOFF1 to plain sfnt.
- Imported fonts register in the render worker as user:<Face> families
  with an italic alias, and are pinned in the frozen render prefs so
  issued invoices can still re-render. Fonts referenced by issued
  invoices are hidden, never deleted.
- Size and tracking compensations tuned for the substitutes apply only
  while the face is not overridden; default output and fingerprint
  goldens are unchanged.
- Settings gets a Fonts section with a licence acknowledgement.

Void packaging:
- Install fonts to /usr/share/fonts/voiced with per-family OFL licences,
  set font_dirs, and add INSTALL/REMOVE scripts that run fc-cache.
  xbps-create carries both scripts (verified in a void-glibc container).
- Fix xbps-create dependency specs in build-xbps.sh.

src/pdf/engine/measure.ts

@@ -2,6 +2,7 @@ import { create, type Font } from "fontkit";
 import { FONT_MANIFEST } from "../fonts/manifest";
 import { familySources, FONT_STACK, stack, type FamilySource } from "../fonts/stack";
 import { resolveFace, roleToken, type RoleName, type TypeToken } from "../fonts/roles";
+import { userFamilySources } from "../fonts/userFontStore";
 
 export interface MeasureInput {
   text: string;
@@ -29,6 +30,29 @@ export interface Measurer {
   missing(text: string, face?: string): number[];
 }
 
+const userFonts = new Map<string, Font>();
+
+/**
+ * The fontkit font of a user-imported family at a weight and style (the file react-pdf resolves for it), or
+ * undefined when `familyName` is not a user family. Parsed once per file and shared by every measurer.
+ */
+export function userFontkitFont(familyName: string, weight: number, italic: boolean): Font | null | undefined {
+  const sources = userFamilySources(familyName);
+  if (sources.length === 0) return undefined;
+  const src = resolveSource(
+    sources.map((s) => ({ file: s.id, fontWeight: s.fontWeight, fontStyle: s.fontStyle })),
+    weight,
+    italic ? "italic" : "normal",
+  );
+  if (!src) return null;
+  let font = userFonts.get(src.file);
+  if (!font) {
+    font = create((sources.find((s) => s.id === src.file) as { bytes: Uint8Array }).bytes) as Font;
+    userFonts.set(src.file, font);
+  }
+  return font;
+}
+
 /** react-pdf's FontFamily.resolve, so the measurer reads the same file the renderer embeds. */
 function resolveSource(sources: FamilySource[], weight: number, style: "normal" | "italic"): FamilySource | undefined {
   const styled = sources.filter((s) => s.fontStyle === style);
@@ -57,6 +81,8 @@ export function createMeasurer(loadBytes: (file: string) => Uint8Array): Measure
   const fonts = new Map<string, Font>();
 
   function load(familyName: string, weight: number, italic: boolean): Font | null {
+    const own = userFontkitFont(familyName, weight, italic);
+    if (own !== undefined) return own;
     const fam = FONT_MANIFEST.families.find((f) => f.family === familyName);
     if (!fam) return null;
     const src = resolveSource(familySources(fam), weight, italic ? "italic" : "normal");