chore(native-lib): drop Node/Python repro folders from this branch

The native-lib/node/repro and native-lib/python/repro folders are regression
guards for the pre-existing Node and Python bindings, covering fixes that
already merged to master independently (PR #121 read-callback exception, PR
#122 streaming queue backpressure). They are unrelated to the new C/Go/Rust
bindings this branch introduces, are not wired into any build/CI, and were
intentionally excluded when the Node/Python docs were extracted (PR #126).

Remove them so they do not re-land on master with this feature. The C and Go
repro folders remain — they exercise the new bindings added here.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: mlischetti