Missingness grid stress

Cross-stratum ledger for incomplete observation. Narrative API catalogue: Missingness.

• Structural — MissingnessSpec / certify_missingness / identify(...; missingness=)
• Dynamical — sequential and survival under handle_missing; generative masks via CausalDynamics
• Observable — :drop / :ipcw / :impute / :ipcw_impute on LMTP, g-comp, mediation; opt-in impute_posterior

Quarto notebook: docs/stress/missingness_grid_stress.qmd

Posterior-only sibling: docs/stress/missingness_posterior_stress.qmd

cd docs/stress && quarto render missingness_grid_stress.qmd

From the CDCS book repo, run the focused edge suites plus smoke harness:

julia --project=. --threads=auto scripts/stress_harness/run_missingness_validation.jl