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/render.test.ts

@@ -1,6 +1,6 @@
 /**
  * Renderer unit tests — pure-function assertions for render.ts, smartypants.ts,
- * and print-css.ts. No Playwright, no PDF generation.
+ * and print-css.ts. No browser, no PDF generation.
  */
 
 import { describe, expect, test } from "bun:test";