Drop the mermaid import from the markdown module. The extension only emits <pre class="mermaid">, so initialize mermaid in the app entry instead. Use explicit .js specifiers plus a bundler extensionAlias so both the NodeNext CLI build and the web build resolve the sources.
Change the proxy path from `/journal` to `/.ttrpg` and ensure the
MQTT broker URL points to localhost:3000 during development to
match the CLI server configuration.
Remove the webpack-based file indexing strategy in favor of a proxy
approach. The dev server now proxies content requests to a local CLI
server, simplifying the data loading logic and removing webpack-specific
types and loaders.