feat: Move VaultCreate invariants from ValidVault to VaultCreate

Introduce VaultInvariantData to collect vault and MPTokenIssuance
snapshots during visitInvariantEntry, then implement the six
ttVAULT_CREATE-specific post-conditions in VaultCreate::finalizeInvariants
(empty vault, pseudo-account linkage). ValidVault now passes through
ttVAULT_CREATE in its switch, keeping only the universal vault checks and
the cross-transaction sentinel that guards against other tx types creating
vaults.

include/xrpl/tx/invariants/VaultInvariantData.h

@@ -0,0 +1,76 @@
+#pragma once
+
+#include <xrpl/basics/Number.h>
+#include <xrpl/basics/base_uint.h>
+#include <xrpl/protocol/AccountID.h>
+#include <xrpl/protocol/Asset.h>
+#include <xrpl/protocol/MPTIssue.h>
+#include <xrpl/protocol/STLedgerEntry.h>
+
+#include <optional>
+#include <vector>
+
+namespace xrpl {
+
+/**
+ * @brief Collects vault and share-issuance snapshots from ledger entry visits.
+ *
+ * Used by per-transaction invariant checks (e.g. VaultCreate) that need
+ * vault and MPTokenIssuance state without the full balance-delta tracking
+ * that ValidVault maintains.
+ */
+class VaultInvariantData
+{
+public:
+    struct Vault
+    {
+        uint256 key = beast::kZero;
+        Asset asset;
+        AccountID pseudoId;
+        AccountID owner;
+        uint192 shareMPTID = beast::kZero;
+        Number assetsTotal = 0;
+        Number assetsAvailable = 0;
+        Number assetsMaximum = 0;
+        Number lossUnrealized = 0;
+
+        static Vault
+        make(SLE const&);
+    };
+
+    struct Shares
+    {
+        MPTIssue share;
+        std::uint64_t sharesTotal = 0;
+        std::uint64_t sharesMaximum = 0;
+
+        static Shares
+        make(SLE const&);
+    };
+
+    void
+    visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after);
+
+    [[nodiscard]] std::vector<Vault> const&
+    afterVaults() const
+    {
+        return afterVault_;
+    }
+
+    [[nodiscard]] std::vector<Vault> const&
+    beforeVaults() const
+    {
+        return beforeVault_;
+    }
+
+    /** Find shares in afterMPTs_ whose mptID matches. */
+    [[nodiscard]] std::optional<Shares>
+    findShares(uint192 const& mptID) const;
+
+private:
+    std::vector<Vault> afterVault_;
+    std::vector<Vault> beforeVault_;
+    std::vector<Shares> afterMPTs_;
+};
+
+}  // namespace xrpl

include/xrpl/tx/transactors/vault/VaultCreate.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <xrpl/tx/Transactor.h>
+#include <xrpl/tx/invariants/VaultInvariantData.h>
 
 namespace xrpl {
 
@@ -38,6 +39,9 @@ public:
         XRPAmount fee,
         ReadView const& view,
         beast::Journal const& j) override;
+
+private:
+    VaultInvariantData data_;
 };
 
 }  // namespace xrpl