refactor(evidence): unify formulas with typed evidence

harness/tht/evidence/session.py

@@ -55,7 +55,45 @@ def project_session(
             "esito": "accettata" if decision.type == "evidence_accepted" else "scartata",
             "decision_seq": decision.seq,
         }
-    return list(entries.values())
+    return list(entries.values()) + _formula_proposals(decisions, linking)
+
+
+def _formula_proposals(decisions: list["DecisionRecord"], linking: "SchemaLinking") -> list[dict]:
+    """Project locally approved F4 formulas without representing them as Evidence.
+
+    A proposal remains in the persisted session artifact until a separate curator
+    imports, reviews, and publishes it in the workspace repository.
+    """
+    approved = {
+        decision.detail: decision.seq
+        for decision in decisions
+        if decision.type == "concept_formula_approved" and decision.detail
+    }
+    proposals = []
+    for formula in linking.concept_formulas:
+        if not isinstance(formula, dict):
+            continue
+        concept = formula.get("concept")
+        sql = formula.get("sql")
+        columns = formula.get("columns")
+        if not isinstance(concept, str) or not isinstance(sql, str) or not isinstance(columns, list):
+            continue
+        # A referenced published Formula Evidence is already represented by its
+        # Evidence receipt/citation, so it must not be reintroduced as a proposal.
+        evidence_id = formula.get("evidence_id", formula.get("id", ""))
+        if isinstance(evidence_id, str) and evidence_id.startswith("evidence:"):
+            continue
+        proposals.append({
+            "schema_version": 1,
+            "kind": "formula_proposal",
+            "publication": "session_only",
+            "concept": concept,
+            "columns": columns,
+            "sql": sql,
+            "sources": formula.get("sources", []),
+            "decision_seq": approved.get(concept),
+        })
+    return proposals
 
 
 @dataclass(frozen=True)