Keep --json stdout clean when oxc-parser falls back to WASM on WebContainers #46

--json mode promises exactly one JSON document on stdout. On StackBlitz WebContainers, oxc-parser's webcontainer-fallback.cjs installs the WASM build during import("oxc-parser") and prints [oxc-parser] Downloading… with console.log. That line lands in front of the JSON, and JSON.parse on the output fails.

Only that environment is affected; native platforms load the binding without output.

Done when: loading the parser can no longer write to stdout (for example, by redirecting console.log to stderr while import("oxc-parser") runs, or by detecting the fallback). A test proves that a parser load that logs does not reach stdout.