interfaces: Implement snapshot loading functionality in node interface

- Added a new virtual method `loadSnapshot` to the node interface for loading UTXO snapshots.
- Introduced a handler for tracking snapshot load progress with `handleSnapshotLoadProgress`.
- Updated the implementation in `interfaces.cpp` to activate the snapshot using the provided file and metadata.

This enhancement exposes UTXO snapshots loading functionaility to the GUI.

Author: D33r-Gee

src/interfaces/node.h

@@ -12,6 +12,7 @@
 #include <net_types.h>
 #include <netaddress.h>
 #include <netbase.h>
+#include <node/utxo_snapshot.h>
 #include <support/allocators/secure.h>
 #include <util/translation.h>
 
@@ -204,6 +205,9 @@ class Node
     //! List rpc commands.
     virtual std::vector<std::string> listRpcCommands() = 0;
 
+    //! Load UTXO Snapshot.
+    virtual bool loadSnapshot(AutoFile& afile, const node::SnapshotMetadata& metadata, bool in_memory) = 0;
+
     //! Get unspent output associated with a transaction.
     virtual std::optional<Coin> getUnspentOutput(const COutPoint& output) = 0;
 
@@ -233,6 +237,10 @@ class Node
     using ShowProgressFn = std::function<void(const std::string& title, int progress, bool resume_possible)>;
     virtual std::unique_ptr<Handler> handleShowProgress(ShowProgressFn fn) = 0;
 
+     //! Register handler for snapshot load progress.
+    using SnapshotLoadProgressFn = std::function<void(double progress)>;
+    virtual std::unique_ptr<Handler> handleSnapshotLoadProgress(SnapshotLoadProgressFn fn) = 0;
+
     //! Register handler for wallet loader constructed messages.
     using InitWalletFn = std::function<void()>;
     virtual std::unique_ptr<Handler> handleInitWallet(InitWalletFn fn) = 0;

src/node/interfaces.cpp

@@ -38,6 +38,7 @@
 #include <node/kernel_notifications.h>
 #include <node/transaction.h>
 #include <node/types.h>
+#include <node/utxo_snapshot.h>
 #include <node/warnings.h>
 #include <policy/feerate.h>
 #include <policy/fees.h>
@@ -356,6 +357,11 @@ class NodeImpl : public Node
         return ::tableRPC.execute(req);
     }
     std::vector<std::string> listRpcCommands() override { return ::tableRPC.listCommands(); }
+    bool loadSnapshot(AutoFile& coins_file, const SnapshotMetadata& metadata, bool in_memory) override
+    {
+        auto activation_result{chainman().ActivateSnapshot(coins_file, metadata, in_memory)};
+        return activation_result.has_value();
+    }
     std::optional<Coin> getUnspentOutput(const COutPoint& output) override
     {
         LOCK(::cs_main);