refactor(make-pdf): print through Aside first, the bundled browser otherwise

asideClient.ts replaces the direct $B client with one render() call per PDF (the exact option mapping the browse pdf command had: paper, margins, header/footer/page numbers, tagged, outline, printBackground, preferCSSPageSize, Paged.js wait); the diagram pre-pass, oversized-image downscale and DOCX rasters each run as one render script with per-fence try/catch; exit 4 now means no browser is available and names both remedies; $P setup reports which engine it found. The e2e gates run on whichever engine is present, so the Linux lane exercises the fallback.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

make-pdf/test/e2e/ci-prereqs.test.ts

@@ -25,6 +25,10 @@ const EXPECT_BINARIES = process.env.GSTACK_EXPECT_BINARIES === "1";
 describe("gate prerequisites (CI tripwire)", () => {
   test.skipIf(!EXPECT_BINARIES)("gate artifacts and tools exist when the lane promises them", () => {
     const missing: string[] = [];
+    // Aside itself is deliberately NOT asserted: CI runners have no Aside. The
+    // gates print through gstack's own browse binary there (the fallback in
+    // lib/aside-render), so THAT build artifact is promised alongside the
+    // make-pdf binary, the diagram bundle, and poppler.
     for (const rel of [
       "make-pdf/dist/pdf",
       "browse/dist/browse",