Migrate lib-commons Observability APIs to lib-observability

When to use

• Application imports one or more lib-commons observability packages/symbols listed in the mapping table below
• Team decision to eliminate deprecation warnings from lib-commons shims
• lib-commons deprecation notices appear in IDE or go vet output
• Application no longer builds because lib-commons has removed observability APIs and source imports still reference them

Skip when

• Application already imports lib-observability for all observability concerns
• Application has no imports of the lib-commons observability packages/symbols listed below
• Application is lib-commons itself

Do NOT skip when:

• "The app only imports log/ from lib-commons" → still migrate; log is an observability target
• "The app uses streaming/kafka" → streaming is out of scope; only observability packages and HTTP/gRPC observability middleware migrate
• "The app uses commons/opentelemetry for tracing bootstrap" → migrate when lib-observability/tracing exposes the target API (helper-only files first, bootstrap when type boundaries allow)
• "go list or go build fails because lib-commons removed the observability APIs" → still migrate; this skill performs static source rewrites against the known mapping table even when the source packages no longer exist