fix: serialise wsdb node-delete key as canonical uint256

decrement_node_reference_count passed the raw fr nodeHash to delete_value,
while write_node/read_node wrap it in FrKeyType (uint256). In bb the raw fr
went through serialise_key's explicit uint256_t overload (implicit fr->uint256
conversion), so all three agreed. The extracted lmdblib replaced that overload
with a generic serialise_key<T> template, which binds fr exactly and emits the
field's Montgomery-form bytes instead of canonical uint256 bytes. Node deletes
then targeted the wrong key, collaterally deleting retained nodes during unwind
and corrupting the tree (the l1_to_l2 cross_chain e2e regression). Wrap the key
in FrKeyType at the delete site so all node ops serialise the key identically.

Also add native-packages/.clang-format (copied from barretenberg/cpp) so the
new C++ packages format to bb's style.

Author: charlielye

native-packages/.clang-format

@@ -0,0 +1,26 @@
+PointerAlignment: Left
+ColumnLimit: 120
+IndentWidth: 4
+BinPackArguments: false
+BinPackParameters: false
+Cpp11BracedListStyle: false
+AlwaysBreakAfterReturnType: None
+AlwaysBreakAfterDefinitionReturnType: None
+PenaltyReturnTypeOnItsOwnLine: 1000000
+BreakConstructorInitializers: BeforeComma
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterClass: false
+  AfterEnum: false
+  AfterFunction: true
+  AfterNamespace: false
+  AfterStruct: false
+  AfterUnion: false
+  AfterExternBlock: false
+  BeforeCatch: false
+  BeforeElse: false
+  SplitEmptyFunction: false
+  SplitEmptyRecord: false
+  SplitEmptyNamespace: false
+AllowShortFunctionsOnASingleLine : Inline
+SortIncludes: true

native-packages/wsdb/cpp/src/merkle_tree/lmdb_store/lmdb_tree_store.cpp

@@ -5,18 +5,18 @@
 // =====================
 
 #include "merkle_tree/lmdb_store/lmdb_tree_store.hpp"
-#include "merkle_tree/tree_db_stats.hpp"
 #include "barretenberg/common/serialize.hpp"
 #include "barretenberg/crypto/merkle_tree/indexed_leaf.hpp"
 #include "barretenberg/crypto/merkle_tree/types.hpp"
 #include "barretenberg/ecc/curves/bn254/fr.hpp"
-#include "lmdblib/lmdb_db_transaction.hpp"
-#include "lmdblib/lmdb_helpers.hpp"
-#include "lmdblib/lmdb_store_base.hpp"
 #include "barretenberg/numeric/uint128/uint128.hpp"
 #include "barretenberg/numeric/uint256/uint256.hpp"
 #include "barretenberg/serialize/msgpack_impl.hpp"
 #include "lmdb_tree_store.hpp"
+#include "lmdblib/lmdb_db_transaction.hpp"
+#include "lmdblib/lmdb_helpers.hpp"
+#include "lmdblib/lmdb_store_base.hpp"
+#include "merkle_tree/tree_db_stats.hpp"
 #include <cstddef>
 #include <cstdint>
 #include <cstring>
@@ -283,7 +283,11 @@ void LMDBTreeStore::decrement_node_reference_count(const fr& nodeHash, NodePaylo
     }
     if (--nodeData.ref == 0) {
         // std::cout << "Deleting node at " << nodeHash << std::endl;
-        tx.delete_value(nodeHash, *_nodeDatabase);
+        // Wrap in FrKeyType so the node key is serialised identically to write_node/read_node
+        // (canonical uint256 bytes). Passing the raw fr would bind serialise_key's generic
+        // template and emit Montgomery-form bytes, deleting the wrong node.
+        FrKeyType key(nodeHash);
+        tx.delete_value(key, *_nodeDatabase);
         return;
     }
     // std::cout << "Updating node at " << nodeHash << " ref is now " << nodeData.ref << std::endl;