[woksin]

Fixed

• The notEmpty and empty validation rules now treat a string as empty exactly when it contains only Unicode White_Space characters, matching Arc .NET and the Arc frontend: a value of only U+0085 (next line) is now empty, and a value of only U+FEFF (byte order mark) is now content. (Backend not-empty rule disagrees with Arc .NET on which characters are whitespace #188)

[woksin]

Reviewer notes

• Source/Core/validation/evaluateRule.ts: the string emptiness check now uses /^\p{White_Space}*$/u instead of trim(), for both empty and notEmpty. Non-string handling is unchanged. The tsconfig target is ES2022, which supports the u flag with property escapes.
• 10 new specs under for_evaluateRule/when_notEmpty and when_empty: U+0085, ordinary whitespace, empty string, U+FEFF and padded content. The U+0085 and U+FEFF specs fail with trim().
• Local checks: vitest run Source/Core/validation (137 pass), eslint on the validation folder, yarn typecheck. Full CI runs here.
• Review: a quick round with the security lens passed with 0 findings.
• Parity reference: Screenplay decision 0071 and Frontend NotEmptyRule disagrees with the backend on which characters are whitespace Arc#3224.