Extract every Chinese string inside backend logger.{info,warning,error,
debug,exception} calls and inside user-facing jsonify({"error|message":
...}) responses across the listed in-scope modules into
locales/{en,zh}.json under nested namespaces (log.<module>.*,
api.{error,message}.<scope>.*). Locale dictionaries stay structurally
identical; the existing flat frontend-facing keys at log.* / api.* are
left untouched. The locale helper (backend/app/utils/locale.py) now
emits a single deduplicated mirofish.locale warning per (locale, key)
pair when a translation is missing instead of silently returning the
raw key, so unknown keys are visible without crashing requests or
background tasks. A repo-root scripts/check_i18n_logs.py verifier
performs an AST-aware source scan for residual Chinese inside the
in-scope logger/jsonify calls and a recursive parity diff between
en.json and zh.json — both modes pass.
Why: backend logs and API errors previously emitted Chinese-only
strings, leaving English-speaking operators with unreadable log
aggregator output and API consumers with locale-mismatched error
messages. The t() helper and per-thread set_locale propagation already
existed; this change makes every backend caller route through them.
Closes#6
Dominik Seemann