88aa88f605
The vendored markit engine kept `mupdf` external, but a single-file `bun --compile` binary has no node_modules to resolve it from, so the standalone binary aborted at startup with `Cannot find package 'mupdf'` — the otherwise-lazy import is resolved eagerly at boot. Bundle mupdf and embed its WASM blob (scripts/embed-mupdf-wasm.ts, reset after the build); npm and source installs still load mupdf from node_modules. Import mupdf lazily inside the PDF converter so the bundled markit chunk's init stays synchronous: mupdf's top-level await otherwise made the chunk init async and bun's compiled bundler failed to await it through the barrel, exposing the converters before their module-level const tables initialized (undefined EXTENSIONS). Also keeps the ~10MB wasm off non-PDF document conversions.