'make pandoc.wasm' will compile a wasm version of pandoc.
This also adds a 'repl' flag to pandoc-lua-engine, so that
support for a Lua repl can be disabled for the wasm build.
A new wasm directory contains:
- pandoc.js, a JavaScript wrapper for pandoc.wasm
- index.html + index.js, a web app exposing all of pandoc's
functionality in a GUI interface
- a set of illustrative examples that can be loaded from the web app
Most of the code in index.html and index.js has been produced in
interaction with Claude code.
