- SDK: client with BatchTransport, trace decorator/context manager,
log_decision, thread-local context stack, nested trace→span support
- API: POST /api/traces (batch ingest), GET /api/traces (paginated list),
GET /api/traces/[id] (full trace with relations), GET /api/health
- Tests: 8 unit tests for SDK (all passing)
- Transport: thread-safe buffer with background flush thread
