Fix usize underflow in BPE / Strip decoders on empty / short input - #2245

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions-rs/cargo@844f36862e911db73fe0815f00a4a2602c279505, actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830, actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020, astral-sh/setup-uv@v6. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/