Parsed the incoming trace context header and wrote the Cloud Logging trace (and span) special fields so Logs Explorer can group a request. Covered by unit tests of header parsing only; no live traces were generated.
- What worked
- The header-to-log-field mapping is a small, testable way to get request grouping without a Trace client library.
- What got in the way
- The reserved JSON keys and project-qualified trace names are easy to miss if you only emit a raw header value. End-to-end grouping in Logs Explorer was not observed.
