Add bundled TTF fonts, page geometry, column allocator and render model

Static TTF fonts (IBM Plex Sans/Mono, Noto Devanagari/Kannada) with a
fontkit-generated manifest, a verifier and OFL licences. Every family
registers a normal and italic source so fallback stacks cannot throw.
Adds A4/Letter geometry with margin presets, an exact column allocator,
deterministic Indian-grouping money and date formatting, text sanitising
and a pure buildRenderModel.

scripts/fonts/build-manifest.mjs

@@ -0,0 +1,29 @@
+// Regenerates public/fonts/manifest.json from the TTFs under public/fonts/<folder>/.
+// Run: node scripts/fonts/build-manifest.mjs
+import { existsSync, writeFileSync } from "node:fs";
+import path from "node:path";
+import { FONTS_DIR, MANIFEST_PATH, familyFolders, inspectFont, ttfFiles } from "./lib.mjs";
+
+const families = [];
+for (const folder of familyFolders()) {
+  const files = ttfFiles(folder);
+  if (files.length === 0) continue;
+  const inspected = files.map((file) => inspectFont(folder, file));
+  const names = new Set(inspected.map((f) => f.familyName));
+  if (names.size !== 1) {
+    throw new Error(`${folder}: mixed family names ${[...names].join(", ")}`);
+  }
+  const licenseFile = "OFL.txt";
+  if (!existsSync(path.join(FONTS_DIR, folder, licenseFile))) {
+    throw new Error(`${folder}: missing ${licenseFile}`);
+  }
+  const fonts = inspected
+    .map((f) => f.info)
+    .sort((a, b) => a.weight - b.weight || a.style.localeCompare(b.style) || a.file.localeCompare(b.file));
+  families.push({ family: [...names][0], folder, license: "OFL-1.1", licenseFile, fonts });
+}
+
+writeFileSync(MANIFEST_PATH, `${JSON.stringify({ version: 1, families }, null, 2)}\n`);
+console.log(
+  `manifest.json: ${families.length} families, ${families.reduce((n, f) => n + f.fonts.length, 0)} fonts`,
+);