Looks nice! I would suggest to pointing users to a small demo csv file and query that can be quickly loaded/pasted to see it working. Or even have a "Load example CSV and query" button.
Cool stuff, we are also building in the space, currently adding Python support with Pyodide. I would recommend you add your live website at the top of the README so people can find it easily (we had a lot of views that way for https://github.com/pretzelai/pretzelai). Also, we added a simple text2sql "Ask AI" that users loved, maybe your users will like it too.
Is there support for DuckDB in JupyterLite in WASM in WhatTheDuck or pretzelai?
datasette-lite can load [remote] sqlite and Parquet but not yet DuckDB (?) with Pyodide in WASM, and there's also JupyterLite as a datasette plug-in:
https://github.com/simonw/datasette-lite
I liked SQL workbench (https://news.ycombinator.com/item?id=39537794) which has the same core ideas but more usable features at this point (query history, parquet support and charts) - if you hadn't seen it maybe some of its features will inspire you.
SQL workbench also uses https://perspective.finos.org/ for tables. It's a WASM table library which pairs nicely with duckdb and works well with large tables.
IDE support is definitely one area where DuckDB could be better. My current workflow is to edit SQL files in VS Code and then use ‘.read’ within the DuckDB CLI.