What

Jaeger and Zipkin exporters currently stub the protobuf serialization path (CLAUDE.md:98). Complete the implementation so spans flow end-to-end to both backends.

• Current: Exporters exist as skeletons; protobuf wire format not serialized
• Expected: Spans round-trip to a Jaeger all-in-one and Zipkin v2 backend in integration tests
• Scope: include/kcenon/monitoring/exporters/jaeger_*, zipkin_*, matching src/

Why

• Observability pipelines in practice still rely on Jaeger/Zipkin; OTLP alone is insufficient for many deployments
• Incomplete exporters present as broken to any real adopter
• Closes a known gap tracked in CLAUDE.md

How

Technical Approach

1. Pull in jaegertracing/jaeger-idl or precompiled .proto
2. Implement Span -> Jaeger Batch mapping (tags, logs, references)
3. Implement Span -> Zipkin v2 JSON + protobuf mapping
4. Integration tests using jaegertracing/all-in-one and openzipkin/zipkin containers

Acceptance Criteria

• Spans visible in Jaeger UI from integration test
• Zipkin v2 API accepts exported spans
• Round-trip tests for tag/log/reference fidelity
• Benchmarks vs OTLP exporter recorded