These files bypassed the i18n table entirely, so a user running LANG=en still
got Chinese order logs. Migrating them surfaced structural duplication too: the
five order paths each spelled out their own 'quantity invalid' string, now one
key parameterised by an order-kind label.
Also fixes a type that carried display text as its domain: TrendLabel was
'做多' | '做空' | '无信号', so the engine's snapshot value *was* the Chinese
string and English rendering depended on matching it. Now 'long' | 'short' |
'none', translated at the edge.
Order-coordinator tests asserted the Chinese literals, which is exactly what
made the gap invisible; they now assert the resolved key so they hold in either
language.
39 new translation keys. 271 pass; tsc and oxlint clean.