docs(observability): define Langfuse and structured logging strategy
Why:
- Establish separate observability systems for LLM tracing, prompt iteration, evaluation, operational logs, and durable application audit records.
Changes:
- Define Langfuse traces, prompt labels, feedback scores, evaluation workflows, redaction rules, and correlation identifiers.
- Define structlog-based JSON logging, request context propagation, event naming, log levels, and privacy requirements.
Impact:
- Langfuse remains the LLM observability plane, while Postgres remains the durable audit and billing source of truth.
- Application logs must avoid secrets and raw sensitive payloads.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Ali Zarinkolah
e9caeaa4d8