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.

package.json

@@ -14,7 +14,9 @@
     "app:dev": "tauri dev",
     "app:build": "tauri build --features custom-protocol",
     "app:build:windows": "tauri build --runner cargo-xwin --target x86_64-pc-windows-msvc --features custom-protocol",
-    "app:build:windows:offline": "tauri build --runner cargo-xwin --target x86_64-pc-windows-msvc --features custom-protocol --config '{\"bundle\":{\"windows\":{\"webviewInstallMode\":{\"type\":\"offlineInstaller\"}}}}'"
+    "app:build:windows:offline": "tauri build --runner cargo-xwin --target x86_64-pc-windows-msvc --features custom-protocol --config '{\"bundle\":{\"windows\":{\"webviewInstallMode\":{\"type\":\"offlineInstaller\"}}}}'",
+    "fonts:verify": "node scripts/fonts/verify.mjs",
+    "fonts:manifest": "node scripts/fonts/build-manifest.mjs"
   },
   "dependencies": {
     "@carbon/icons-react": "^11.89.0",
@@ -35,6 +37,7 @@
     "@types/react": "^19.2.0",
     "@types/react-dom": "^19.2.0",
     "@vitejs/plugin-react": "^5.2.0",
+    "fontkit": "2.0.4",
     "pdfjs-dist": "6.4.299",
     "sass": "^1.105.1",
     "typescript": "^5.9.3",