Raw Jaeger trace dumps (with and without incoming traceparent) plus a
derived span inventory and README describing the pre-migration span shape.
Captured from master da3901c release build against a local Jaeger; see
docs/tracing-baseline/pre-migration/README.md for the procedure and the
single span-neutral deviation (aux listen port 8088->18088).
Artifact branch only; /docs/* is gitignored, files force-added deliberately.
