# Architecture

`core/data.ts` performs bounded static parsing into JSON-compatible values while
retaining raw numeric and cell-inference evidence. `core/query.ts` tokenizes the
fixed SQL-like and path grammars, exposes their bounded syntax trees, interprets
field paths and returns an explain plan; it never compiles or evaluates code.

`core/duckdb.ts` is a separately selected adapter for the locally bundled
single-threaded DuckDB-WASM MVP build. A lexical security gate accepts exactly
one `SELECT` statement and rejects semicolons plus mutation, attachment,
extension, file and configuration keywords before DuckDB performs its complete
SQL parse. The adapter serializes at most 10,000 bounded rows into an in-memory
table, disables external access and extension auto-install/auto-load, caps
database memory at 128 MiB, limits results to 1,000 rows and terminates the
disposable worker after completion, cancellation or a hard deadline.

React retains the last valid dataset/result after errors and suppresses stale
asynchronous results. Relative assets and a same-origin service worker support
nested offline deployment. The static host serves hashed WASM as
`application/wasm` with immutable caching and grants only the CSP allowances
needed for same-origin WASM and workers.