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
Background threads (graph building, simulation prep, report generation,
profile generation) now inherit the requesting user's locale preference.
Previously these fell back to 'zh' because Flask request context was
unavailable in spawned threads.
Dominik Seemann
ghostubborn