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.

src/lib/imageSize.ts

@@ -0,0 +1,62 @@
+export interface ImageSize {
+  width: number;
+  height: number;
+}
+
+function base64ToBytes(b64: string): Uint8Array {
+  const bin = atob(b64);
+  const out = new Uint8Array(bin.length);
+  for (let i = 0; i < bin.length; i++) out[i] = bin.charCodeAt(i);
+  return out;
+}
+
+const u16 = (b: Uint8Array, i: number) => (b[i] << 8) | b[i + 1];
+const u32 = (b: Uint8Array, i: number) => ((b[i] << 24) | (b[i + 1] << 16) | (b[i + 2] << 8) | b[i + 3]) >>> 0;
+
+function pngSize(b: Uint8Array): ImageSize | null {
+  const sig = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
+  if (b.length < 24 || sig.some((v, i) => b[i] !== v)) return null;
+  return { width: u32(b, 16), height: u32(b, 20) };
+}
+
+function jpegSize(b: Uint8Array): ImageSize | null {
+  if (b.length < 4 || b[0] !== 0xff || b[1] !== 0xd8) return null;
+  let i = 2;
+  while (i + 3 < b.length) {
+    if (b[i] !== 0xff) {
+      i++;
+      continue;
+    }
+    const marker = b[i + 1];
+    if (marker === 0xff) {
+      i++; // fill byte
+      continue;
+    }
+    // Standalone markers carry no length.
+    if (marker === 0x01 || (marker >= 0xd0 && marker <= 0xd8)) {
+      i += 2;
+      continue;
+    }
+    const isSof =
+      marker >= 0xc0 && marker <= 0xcf && marker !== 0xc4 && marker !== 0xc8 && marker !== 0xcc;
+    if (isSof) {
+      if (i + 8 >= b.length) return null;
+      return { height: u16(b, i + 5), width: u16(b, i + 7) };
+    }
+    i += 2 + u16(b, i + 2);
+  }
+  return null;
+}
+
+/** Pixel size of a PNG or JPEG data URI, or null when it is another format or malformed. */
+export function imageSizeFromDataUri(uri: string): ImageSize | null {
+  const comma = uri.indexOf(",");
+  if (!uri.startsWith("data:") || comma < 0) return null;
+  try {
+    const bytes = base64ToBytes(uri.slice(comma + 1));
+    const size = pngSize(bytes) ?? jpegSize(bytes);
+    return size && size.width > 0 && size.height > 0 ? size : null;
+  } catch {
+    return null;
+  }
+}

src/lib/pdf.tsx

@@ -1,5 +1,6 @@
 import { pdf } from "@react-pdf/renderer";
 import { save } from "@tauri-apps/plugin-dialog";
+import { registerPdfFonts } from "../pdf/fonts";
 import { InvoiceDocument, type InvoicePdfProps } from "../pdf/InvoiceDocument";
 import { api } from "./api";
 import type { BankAccount, Invoice, Settings } from "./types";
@@ -64,6 +65,7 @@ export async function buildPdfProps(
 
 /** Render props straight to a PDF blob. */
 export async function renderPdfBlob(props: InvoicePdfProps): Promise<Blob> {
+  registerPdfFonts();
   return pdf(<InvoiceDocument {...props} />).toBlob();
 }