Replace the sample data with synthetic fixtures and regenerate goldens and thumbnails

The template harness, tests and thumbnails now use a neutral vendor, bank account and
a generated sample wordmark (scripts/logo/make-sample-logo.mjs). Layout goldens and the
14 picker thumbnails are regenerated. Fixture strings keep their original lengths where
layout tests depend on them.

src/pdf/engine/logo.test.ts

@@ -5,7 +5,7 @@ const BOX = { w: 170, h: 54 };
 const base = { box: BOX, availableWidth: 299, minTextWidth: 160 };
 
 describe("computeClassicLogoPlacement", () => {
-  it("the Test Vendor trimmed 4.6:1 logo is width-limited and stacks above the text", () => {
+  it("the sample trimmed 4.6:1 logo is width-limited and stacks above the text", () => {
     const p = computeClassicLogoPlacement({ ...base, aspect: 4.6 });
     expect(p.w).toBeCloseTo(170, 6);
     expect(p.h).toBeCloseTo(170 / 4.6, 6);