Internationalization (i18n) support for ALIEN

[zysftd]

I'd like to propose adding i18n support to ALIEN and would appreciate some initial feedback. Considering two approaches.

Option A: _(key) + JSON
_("Energy") wraps strings, looks up translations from a JSON file at runtime, falls back to the original text if not found.

Option B: gettext
GNU standard with .po files and xgettext for automatic string extraction.

I lean toward Option A since it keeps things simple and works well on Windows without extra dependencies. A complete Chinese translation (~600 strings, full GUI coverage) is already done in a fork and can be contributed once the approach is settled.

Looking forward to your feedback.