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/measure.test.tsx

@@ -12,7 +12,7 @@ const SAMPLES: string[] = [
   "Voice-over session 12 - narration for module 3",
   "Total ₹1,23,456.78",
   "AVATAR WAVE To Ty Yo",
-  "vendor.name@examplestudios.co.in",
+  "anon.longsurname.voiceover@examplestudios.co.in",
   "29ABCDE1234F1Z5",
   "office fi fl ffi final",
   "BILLED TO",
@@ -130,7 +130,7 @@ describe("measurer helpers", () => {
   });
 
   it("round-trips chunkIdentifier output", () => {
-    const id = "vendor.name@examplestudios.co.in";
+    const id = "anon.longsurname.voiceover@examplestudios.co.in";
     expect(chunkIdentifier(id, 12).join("")).toBe(id);
   });
 });