Add zh-TW locale resources and wire it through language selection,
persistence, and system-locale detection. Also add static shape typing
for zh-TW to prevent future key drift from zh-CN.
Constraint: Keep changes minimal and localized to i18n + language pickers
Rejected: Partial zh-TW translation only for language section | fails full locale support goal
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep zh-TW key shape locked to zh-CN when adding new translation keys
Tested: npm run -s build (openless-all/app)
Not-tested: Manual runtime walkthrough on all platform shells
H-Chris233
e50bc17a15