New complete language packs (431 keys each, key-aligned with en-US):
French, German, Russian, Japanese, Spanish, Portuguese — contributed
via the translation subagent, reviewed for key parity and genuine
translations.
Runtime discovery replaces compiled-in packs: include_str! and the
Language enum are gone; every <code>.yaml found in the searched
directories registers a language, so adding one needs neither a
rebuild nor a code change. Each pack names itself via its
"language.name" key (the endonym), which the pickers display. The
menu bar language submenu is built from the discovered packs (menu ids
in the new LANG_ITEM_BASE range, dispatched before the registry), the
preferences combo enumerates them the same way, and switching goes
through set_language_code. The C++-style LangZh/LangEn registry
actions are removed (menu ids 303/304 stay reserved). pack_dirs gains
the system-install layout <exe>/../share/oak/i18n, and en.yaml is
renamed en-US.yaml so the discovered code matches the fallback code.
Test hardening (a Windows/Linux CI flake chain exposed by this work):
the two language-test mutexes are one shared poison-tolerant mutex;
every test that flips the process language restores en-US before
releasing it; tests that match menus by localized labels take the lock
and pin en-US first.
Mike-Solar
4622a1af1e