The single most important architectural fix vs ChironeWp3: ALL helpers consult
effective_decisions() instead of raw list_decisions(), so the reopen-aware view is
consistent everywhere (fixes the bug where approved_ctes/advance_problems conflated
stale pre-reopen decisions with new ones).
Model (corrected during TDD):
- current_phase folds the audit (excluding retracted) with guard 'n == cur' --
already reopen-aware (old phase_approved:N after reopen to M<N don't advance).
- effective_decisions = decisions whose phase <= current_phase. A sql_approved at
phase 7 is stale when current_phase=4 after a rollback to F4, even if in the ledger.
Rollback to F4 does NOT invalidate decisions of phases 1-3 (they stay effective).
- decision_retracted markers excluded (audit-only).
Also: session/models.py ported (SchemaLinking + Candidate with grounded_values D14a
+ concept_formulas D14b). MAX_PHASE/PHASE_NAMES read from workflow.yaml via
load_workflow() (no duplication). Strada 2: ladder if-phase-N kept for now,
generic prerequisites evaluator (F2 full) deferred.
7 phase tests + 20 total passing.