fix(diagnostics): expose translation failure details

[kfstorm]

Summary

Translation failures now retain the original exception message from PySubtrans through the Job API and persistence layer. Failed Job details show that message directly, including provider errors, instead of replacing it with Translation failed.

• Preserve collected batch errors even when PySubtrans also reports an aborted translation.
• Keep error codes and structured context in expandable diagnostic details, remove duplicate help text, and update the diagnostic label across all interface languages.
• Preserve multiline messages, wrap long values, and keep the warning icon readable.
• Add a shared UTC timestamp format with millisecond precision for server, access, and translation logs. Docker, development, and E2E startup commands load the same configuration before application startup.

Impact

The existing error.message field stores the failure reason; no database migration is required. Error details already reduced to a generic message cannot be recovered from existing Job records. A new translation attempt records its actual failure reason.

Custom Uvicorn startup commands can enable the shared log format with --log-config cueweaver/logging.json.