Iteration 03

Feature 1/8 (bar_categorical_recurrence_rate) COMPLETE — all 16 pipeline stages green. This fire added the ADR, the recurr:* mise tasks (with the regenerate-and-diff oracle drift guard and an explicit nextest filterset so the robustness + schema-contract gates actually run) and 6 slash-command wrappers; ran recurr:check-full to GREEN over BOTH symbols; and held a per-feature adversarial Attacker+Defender challenge (10 findings, all refuted — the bit-exact estimator survives every quantization / tie-grouping / oracle-independence probe). The batch PR is now open as terrylica/opendeviationbar-py#544 with the per-feature oracle-residual table and Challenge-and-Held section. Next: feature 2/8 — bar_sign_markov_flux (directional-flow asymmetry of the up/flat/down sign sequence).