Fix header overlap in invoice PDF and Bongbetic wordmark on light theme

react-pdf wraps text once at the first flex measure; when yoga then shrank
the vendor column the cached lines ran under the INVOICE meta column. The
header now pins column widths (299 + 24 + 192 pt), sizes the logo from its
own aspect (stacked above the text when it would leave under 160 pt), uses
absolute per-Text line heights, and turns hyphenation off.

Also: repeating table header with an orphan-header guard, wrap=false rows,
Page n of N footer, GSTIN printed only when present, one Text per address
line, HTML twin header grid. The light-theme header showed the white-text
wordmark; the ternary was inverted.

Adds vitest + pdfjs-dist harness that fails on the old document (address
overlaps Invoice No.) and passes on the new one.

package.json

@@ -9,6 +9,7 @@
     "dev": "vite",
     "build": "tsc --noEmit && vite build",
     "preview": "vite preview",
+    "test": "vitest run",
     "tauri": "tauri",
     "app:dev": "tauri dev",
     "app:build": "tauri build --features custom-protocol",
@@ -33,8 +34,13 @@
     "@types/react": "^19.2.0",
     "@types/react-dom": "^19.2.0",
     "@vitejs/plugin-react": "^5.2.0",
+    "pdfjs-dist": "6.4.299",
     "sass": "^1.105.1",
     "typescript": "^5.9.3",
-    "vite": "^7.3.6"
+    "vite": "^7.3.6",
+    "vitest": "^5.0.3"
+  },
+  "optionalDependencies": {
+    "@napi-rs/canvas": "^1.0.10"
   }
 }