Drop the progressive benchmark, remove dead wrap scaffolding

Review fallout from removing progressive publication.

The Live benchmark existed to compare atomic against progressive delivery:
compareModelBackedReports measures goToFirstVariantMs improvement of one
over the other. With progressive gone it measures nothing against nothing.
Worse, benchmark-live.mjs still passed `progressive` to bootFixtureSession,
which no longer accepts it, so `--delivery progressive` was silently
ignored and would have emitted reports labeled progressive that actually
ran atomic. Silent wrong data is worse than a crash. It was built for
progressive, so it goes with progressive: benchmark-live.mjs, its lib, its
test, and the bench:live script. If an atomic latency baseline is wanted
later, that is a smaller thing built on purpose.

live-wrap.mjs: sourceOriginalLines was assigned and never read.

Both found by review bots on #381 (Copilot).

Assisted-by: Claude Code

skill/scripts/live-wrap.mjs

@@ -230,7 +230,6 @@ The agent should insert variant HTML at insertLine.`);
   // Strip only the COMMON minimum leading whitespace across the picked lines;
   // `deindentContent` on the accept side already mirrors this convention.
   let originalLines = lines.slice(startLine, endLine + 1);
-  const sourceOriginalLines = [...originalLines];
 
   // Buffer-aware "original" content: if the user has pending manual edits for
   // this page whose originalText appears in the picked source range, apply