Fix minor warnings in the console, e.g., set language for some text workloads

The ones we already know about (but let's go through the console again and add them here):

- [x] missing default language
- [ ] some WebGPU operation not being supported
- [x] some internal error in transformers.js/one particular model

Start by rerunning the benchmark's text workloads and inspecting the browser console. Investigate the remaining unchecked WebGPU warning and record the unsupported operation and reproduction context. Done means the known console warnings are resolved or documented with actionable details.

Written by the indexing model from the issue text.