build: keep NLS data and owned regex literals ASCII
Serialize generated NLS JavaScript with ASCII escapes while preserving JSON catalogs and decoded message values. Spell the remaining owned regex characters as Unicode escapes, preserve their matching behavior, and remove the redundant notebook Unicode exemption. Add NLS and workspace-picker coverage.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>