P3: assets' posted and scheduled depreciation, their bases, and the K-1 on the tax basis (defect 13, D-41)

Book value is cost less what the books posted; the schedule's figure is
apart. An asset's acquired date comes from its entry. Contributed
property keeps its section 723 carryover basis apart from its depreciable
basis (the lower of value and adjusted basis), with its 704(c) built-in
gain and method. The K-1 worksheet reports tax-basis capital (Form 1065
Item L) beside the book figures, leaving open what only the CPA knows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-core/tests/kernel_bridge.rs

@@ -461,4 +461,27 @@ proptest! {
             );
         }
     }
+
+    /// kernel::basis_figures at i64 (what Kani's basis_figures_laws
+    /// proved) and at Decimal agree, rule by rule.
+    #[test]
+    fn basis_figures_agree(
+        rule in prop_oneof![
+            Just(ledger_core::BasisRule::Purchase),
+            Just(ledger_core::BasisRule::Carryover723),
+            Just(ledger_core::BasisRule::PersonalUseConversion),
+        ],
+        cost in arb_cents(),
+        adjusted in arb_cents(),
+        fmv in arb_cents(),
+    ) {
+        let i = kernel::basis_figures(rule, cost, adjusted, fmv);
+        let d = kernel::basis_figures(rule, dec(cost), dec(adjusted), dec(fmv));
+        prop_assert_eq!(i.is_some(), d.is_some());
+        if let (Some(i), Some(d)) = (i, d) {
+            prop_assert_eq!(i.tax_basis_723.map(dec), d.tax_basis_723);
+            prop_assert_eq!(dec(i.depreciable_basis), d.depreciable_basis);
+            prop_assert_eq!(i.built_in_gain_704c.map(dec), d.built_in_gain_704c);
+        }
+    }
 }