Workspace tooling

Repo-wide developer-tooling requirements — infrastructure that spans all workspace crates rather than any one subsystem. Residents: test-coverage measurement (Workspace test-coverage mea... (FEAT_0120)), the onboarding golden path (Onboarding golden path + as... (FEAT_0121)), test-execution records (Test-execution records (FEAT_0122)), and the unsafe-code gate (Workspace unsafe-code gate (FEAT_0201)). Candidates for later migration: the complexity gate, the publish-ordering guards.