fix(sol): decode terminal data as UTF-8

[sudhir-intc]

Summary

• Decode SOL terminal input as UTF-8 instead of the legacy ASCII code-page mapping.
• Preserve UTF-8 sequences split across input chunks with a persistent decoder.
• Update focused tests for complete and split multibyte sequences.
• Keep generated core/ and bundles/ runtime output ignored; local builds generate it with npm run build-ext.

Validation

• npm test -- --runInBand --silent
• npm run lint
• npm run build-ext

This is the prerequisite PR for ui-toolkit-angular.