ring:migrate-observability

Migrates a Lerian Go application's direct observability imports from lib-commons (deprecated shims OR already-removed APIs) to lib-observability. Operates in three compatible modes against the same known mapping table: - pre-removal reference mode: when a removal commit is known, inspect the parent/previous lib-commons ref to recover the source-side Deprecated notices and exact migration scope. - deprecated-shim mode: effective lib-commons still ships the shims with `// Deprecated:` notices. - removed-api/break-fix mode: lib-commons has already removed the observability packages/symbols (sources absent, `go list` or `go build` fails on the removed imports). The skill still migrates known source imports/symbols by static source analysis of the application repo. It also applies the companion dependency moves required by the same lib-commons removal train: stable lib-streaming/lib-systemplane bumps and direct systemplane imports moved out of lib-commons. Targets are gated on the lib-observability target API, not on the presence of source-side Deprecated notices. Adds lib-observability to go.mod and validates the build. Scope is strictly observability: deprecated/removed observability packages, commons/net/http observability middleware/span symbols, root commons observability context helpers, commons/opentelemetry, and direct commons/systemplane imports. Does NOT touch infrastructure clients or general commons helpers.

mkdir -p ~/.claude/skills/migrate-observability
curl -L https://claudskills.com/skills/migrate-observability/SKILL.md \
  -o ~/.claude/skills/migrate-observability/SKILL.md