[hle] correct IClientProcess::RegisterClient, impl cmd 3100,3102 for ns:vm (#4376)

ldn had wrong signature
ns:vm had missing function stubs that would make some games assert on missing impl

Signed-off-by: lizzie <lizzie@eden-emu.dev>

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4376
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: Maufeat <sahyno1996@gmail.com>

src/core/file_sys/fssystem/fssystem_hierarchical_integrity_verification_storage.cpp

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -121,6 +124,7 @@ size_t HierarchicalIntegrityVerificationStorage::Read(u8* buffer, size_t size,
 }
 
 size_t HierarchicalIntegrityVerificationStorage::GetSize() const {
+    ASSERT(m_data_size >= 0);
     return m_data_size;
 }