Bridge already had a tracing fmt layer writing to stderr but a Flutter
desktop app launched from Explorer / RDP has no terminal attached so
those records vanish. Add a non-ANSI file appender (best-effort,
4 MiB rotation) at the platform-conventional log path so developers
and beta testers can hand-inspect output:
* Linux: $XDG_STATE_HOME/app.chanora/chanora_flutter/chanora.log
(fallback ~/.local/state/...)
* macOS: ~/Library/Logs/app.chanora.chanora_flutter/chanora.log
* Windows: %LOCALAPPDATA%\app.chanora\chanora_flutter\logs\chanora.log
Expose log_file_path_str() over FRB so the UI can show the path in a
'Save diagnostics' affordance later. Mobile (Android/iOS) returns an
empty string — those platforms still rely on logcat / Console.app.
No DEC-016 conflict: this is local-only, append-only, never
auto-uploaded. The in-memory log sink and export_diagnostics() path
are unchanged. The redacting layer still wraps the in-memory sink;
the new file appender consumes the same tracing events post-filter.
Trigger for this change: a ko-KR Windows 11 tester saw
'BridgeError.invalidCommand(audio not started)' with no way to find
the upstream warn record that documents which cpal call failed. Log
file is now discoverable without a terminal launch.
EdisonJwa
6a077ac7a1