[VFS] Rewrote STFS to use memory mapping

- Replaced old-style buffer, buffer_length with std::span
- Added STFS and SVOD specific Entry and File classes
- Other smaller improvements

src/xenia/vfs/devices/xcontent_devices/stfs_container_entry.cc

@@ -0,0 +1,40 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2025 Xenia Canary. All rights reserved.                          *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/vfs/devices/xcontent_devices/stfs_container_entry.h"
+#include "xenia/vfs/devices/xcontent_devices/stfs_container_file.h"
+
+namespace xe {
+namespace vfs {
+
+StfsContainerEntry::StfsContainerEntry(Device* device, Entry* parent,
+                                       const std::string_view path,
+                                       MappedMemory* data)
+    : XContentContainerEntry(device, parent, path), data_(data) {}
+
+StfsContainerEntry::~StfsContainerEntry() = default;
+
+std::unique_ptr<StfsContainerEntry> StfsContainerEntry::Create(
+    Device* device, Entry* parent, const std::string_view name,
+    MappedMemory* data) {
+  auto path = xe::utf8::join_guest_paths(parent->path(), name);
+  auto entry = std::make_unique<StfsContainerEntry>(device, parent, path, data);
+
+  return std::move(entry);
+}
+
+X_STATUS StfsContainerEntry::Open(uint32_t desired_access, File** out_file) {
+  *out_file = new StfsContainerFile(desired_access, this);
+  return X_STATUS_SUCCESS;
+}
+
+bool StfsContainerEntry::DeleteEntryInternal(Entry* entry) { return false; }
+
+}  // namespace vfs
+}  // namespace xe