fix: harden valuation concurrency and currency scope

jarca_ledger_mcp/application/account_valuation_service.py

@@ -174,6 +174,7 @@ def register_account_valuation(
     ts = now_iso()
     values = (amount_int, currency_norm, (valuation_kind or "balance").strip().lower(), source_norm, source_ref or "", status, memo or "", as_of_at, timezone, optional_ints["cost_basis"], optional_ints["net_contributed"], reported_principal_kind, reported_principal_label, optional_ints["profit"], return_rate, return_basis, optional_ints["principal"], optional_ints["interest"], optional_ints["fee"], definition)
     with db(db_path) as conn:
+        conn.execute("BEGIN IMMEDIATE")
         account = conn.execute("SELECT * FROM accounts WHERE id=?", (account_id,)).fetchone()
         if account is None:
             return fail("not_found", "account not found")
@@ -196,10 +197,10 @@ def register_account_valuation(
             conn.execute("""INSERT INTO account_valuations
             (id,account_id,basis_date,amount,currency,valuation_kind,source_type,source_ref,verification_status,recorded_at,memo,idempotency_key,supersedes_id,correction_reason,as_of_at,timezone,cost_basis,net_contributed,reported_principal_kind,reported_principal_label,profit,return_rate,return_basis,principal,interest,fee,representative_liability_definition)
             VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)""", (valuation_id, account_id, basis, *values[:6], ts, values[6], idempotency_key or "", supersedes_id, correction_reason, *values[7:]))
-        except sqlite3.IntegrityError as exc:
+        except sqlite3.IntegrityError:
             if supersedes_id:
                 return fail("correction_conflict", "valuation already has a correction")
-            return fail("idempotency_conflict", str(exc))
+            return fail("idempotency_conflict", "idempotency_key already has a different payload")
         except Exception as exc:
             return fail("validation_error", str(exc))
         row = conn.execute("SELECT * FROM account_valuations WHERE id=?", (valuation_id,)).fetchone()
@@ -237,7 +238,7 @@ def select_account_valuation(account_id: str, basis_date: str, as_of: bool = Fal
         latest_verified_date = max((x["basis_date"] for x in verified), default="")
         candidate = [
             r for r in leaves
-            if r["verification_status"] != "verified"
+            if r["verification_status"] == "unverified"
             and r["basis_date"] <= basis
             and (r["basis_date"] == basis if not as_of else (not latest_verified_date or r["basis_date"] > latest_verified_date))
         ]