Bundled CJS dependencies (e.g. reading-time) use require() for Node
builtins like 'stream' and 'util'. In ESM output, the esbuild-generated
__require shim throws 'Dynamic require of X is not supported' because
there is no global require in ESM context.
Add platform: 'node' and a banner that injects createRequire from the
'module' builtin, providing a working require() function for the CJS
compatibility layer.
Pre-built output is now committed to the repository so that
Quartz can skip the build step during plugin installation.
The prepare script is removed to prevent redundant builds
when installing from npm/git.