feat(hle/am): implement system applet proxies and observer services

- Add OpenHomeMenuProxy (cmd 110) for QLaunch support

- Add GetSystemProcessCommonFunctions (cmd 450)

- Add Cmd460 stub for system process initialization

- Implement IApplicationObserver and ISystemProcessCommonFunctions services

src/core/hle/service/am/service/all_system_applet_proxies_service.cpp

@@ -1,5 +1,5 @@
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
-// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-FileCopyrightText: Copyright 2026 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include "core/core.h"
@@ -11,6 +11,7 @@
 #include "core/hle/service/am/service/overlay_applet_proxy.h"
 #include "core/hle/service/am/service/system_applet_proxy.h"
 #include "core/hle/service/am/service/system_application_proxy.h"
+#include "core/hle/service/am/service/system_process_common_functions.h"
 #include "core/hle/service/am/window_system.h"
 #include "core/hle/service/cmif_serialization.h"
 
@@ -22,12 +23,15 @@ IAllSystemAppletProxiesService::IAllSystemAppletProxiesService(Core::System& sys
     // clang-format off
     static const FunctionInfo functions[] = {
         {100, D<&IAllSystemAppletProxiesService::OpenSystemAppletProxy>, "OpenSystemAppletProxy"},
+        {110, D<&IAllSystemAppletProxiesService::OpenHomeMenuProxy>, "OpenHomeMenuProxy"},
         {200, D<&IAllSystemAppletProxiesService::OpenLibraryAppletProxyOld>, "OpenLibraryAppletProxyOld"},
         {201, D<&IAllSystemAppletProxiesService::OpenLibraryAppletProxy>, "OpenLibraryAppletProxy"},
         {300, D<&IAllSystemAppletProxiesService::OpenOverlayAppletProxy>, "OpenOverlayAppletProxy"},
         {350, D<&IAllSystemAppletProxiesService::OpenSystemApplicationProxy>, "OpenSystemApplicationProxy"},
         {400, D<&IAllSystemAppletProxiesService::CreateSelfLibraryAppletCreatorForDevelop>, "CreateSelfLibraryAppletCreatorForDevelop"},
         {410, D<&IAllSystemAppletProxiesService::GetSystemAppletControllerForDebug>, "GetSystemAppletControllerForDebug"},
+        {450, D<&IAllSystemAppletProxiesService::GetSystemProcessCommonFunctions>, "GetSystemProcessCommonFunctions"},
+        {460, D<&IAllSystemAppletProxiesService::Cmd460>, "Cmd460"},
         {1000, D<&IAllSystemAppletProxiesService::GetDebugFunctions>, "GetDebugFunctions"},
     };
     // clang-format on
@@ -52,6 +56,21 @@ Result IAllSystemAppletProxiesService::OpenSystemAppletProxy(
     }
 }
 
+Result IAllSystemAppletProxiesService::OpenHomeMenuProxy(
+    Out<SharedPointer<ISystemAppletProxy>> out_system_applet_proxy, ClientProcessId pid,
+    InCopyHandle<Kernel::KProcess> process_handle) {
+    LOG_DEBUG(Service_AM, "called");
+
+    if (const auto applet = this->GetAppletFromProcessId(pid); applet) {
+        *out_system_applet_proxy = std::make_shared<ISystemAppletProxy>(
+            system, applet, process_handle.Get(), m_window_system);
+        R_SUCCEED();
+    } else {
+        LOG_ERROR(Service_AM, "Home menu applet doesn't exist for process_id={}", pid.pid);
+        R_THROW(ResultUnknown);
+    }
+}
+
 Result IAllSystemAppletProxiesService::OpenLibraryAppletProxy(
     Out<SharedPointer<ILibraryAppletProxy>> out_library_applet_proxy, ClientProcessId pid,
     InCopyHandle<Kernel::KProcess> process_handle,
@@ -130,6 +149,18 @@ Result IAllSystemAppletProxiesService::GetSystemAppletControllerForDebug() {
     R_THROW(ResultUnknown);
 }
 
+Result IAllSystemAppletProxiesService::GetSystemProcessCommonFunctions(
+    Out<SharedPointer<ISystemProcessCommonFunctions>> out_system_process_common_functions) {
+    LOG_DEBUG(Service_AM, "called");
+    *out_system_process_common_functions = std::make_shared<ISystemProcessCommonFunctions>(system);
+    R_SUCCEED();
+}
+
+Result IAllSystemAppletProxiesService::Cmd460() {
+    LOG_WARNING(Service_AM, "(STUBBED) called");
+    R_SUCCEED();
+}
+
 Result IAllSystemAppletProxiesService::GetDebugFunctions(
     Out<SharedPointer<IDebugFunctions>> out_debug_functions) {
     LOG_DEBUG(Service_AM, "called");

src/core/hle/service/am/service/all_system_applet_proxies_service.h

@@ -1,5 +1,5 @@
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
-// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
+// SPDX-FileCopyrightText: Copyright 2026 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
@@ -19,6 +19,7 @@ class ILibraryAppletProxy;
 class IOverlayAppletProxy;
 class ISystemAppletProxy;
 class ISystemApplicationProxy;
+class ISystemProcessCommonFunctions;
 class WindowSystem;
 
 class IAllSystemAppletProxiesService final
@@ -31,6 +32,9 @@ private:
     Result OpenSystemAppletProxy(Out<SharedPointer<ISystemAppletProxy>> out_system_applet_proxy,
                                  ClientProcessId pid,
                                  InCopyHandle<Kernel::KProcess> process_handle);
+    Result OpenHomeMenuProxy(Out<SharedPointer<ISystemAppletProxy>> out_system_applet_proxy,
+                             ClientProcessId pid,
+                             InCopyHandle<Kernel::KProcess> process_handle);
     Result OpenLibraryAppletProxy(Out<SharedPointer<ILibraryAppletProxy>> out_library_applet_proxy,
                                   ClientProcessId pid,
                                   InCopyHandle<Kernel::KProcess> process_handle,
@@ -49,6 +53,9 @@ private:
                                                      ClientProcessId pid,
                                                      InCopyHandle<Kernel::KProcess> process_handle);
     Result GetSystemAppletControllerForDebug();
+    Result GetSystemProcessCommonFunctions(
+        Out<SharedPointer<ISystemProcessCommonFunctions>> out_system_process_common_functions);
+    Result Cmd460();
     Result GetDebugFunctions(Out<SharedPointer<IDebugFunctions>> out_debug_functions);
 
 private:

src/core/hle/service/am/service/application_observer.cpp

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: Copyright 2026 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/hle/service/am/service/application_observer.h"
+
+namespace Service::AM {
+
+IApplicationObserver::IApplicationObserver(Core::System& system_)
+    : ServiceFramework{system_, "IApplicationObserver"} {
+    // clang-format off
+    static const FunctionInfo functions[] = {
+        {1, nullptr, "Unknown1"},
+        {2, nullptr, "Unknown2"},
+        {10, nullptr, "Unknown10"},
+        {20, nullptr, "Unknown20"},
+        {30, nullptr, "Unknown30"},
+    };
+    // clang-format on
+
+    RegisterHandlers(functions);
+}
+
+IApplicationObserver::~IApplicationObserver() = default;
+
+} // namespace Service::AM

src/core/hle/service/am/service/application_observer.h

@@ -0,0 +1,16 @@
+// SPDX-FileCopyrightText: Copyright 2026 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/hle/service/service.h"
+
+namespace Service::AM {
+
+class IApplicationObserver final : public ServiceFramework<IApplicationObserver> {
+public:
+    explicit IApplicationObserver(Core::System& system_);
+    ~IApplicationObserver() override;
+};
+
+} // namespace Service::AM

src/core/hle/service/am/service/system_process_common_functions.cpp

@@ -0,0 +1,30 @@
+// SPDX-FileCopyrightText: Copyright 2026 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/hle/service/am/service/application_observer.h"
+#include "core/hle/service/am/service/system_process_common_functions.h"
+#include "core/hle/service/cmif_serialization.h"
+
+namespace Service::AM {
+
+ISystemProcessCommonFunctions::ISystemProcessCommonFunctions(Core::System& system_)
+    : ServiceFramework{system_, "ISystemProcessCommonFunctions"} {
+    // clang-format off
+    static const FunctionInfo functions[] = {
+        {0, D<&ISystemProcessCommonFunctions::GetApplicationObserver>, "GetApplicationObserver"},
+    };
+    // clang-format on
+
+    RegisterHandlers(functions);
+}
+
+ISystemProcessCommonFunctions::~ISystemProcessCommonFunctions() = default;
+
+Result ISystemProcessCommonFunctions::GetApplicationObserver(
+    Out<SharedPointer<IApplicationObserver>> out_observer) {
+    LOG_DEBUG(Service_AM, "called");
+    *out_observer = std::make_shared<IApplicationObserver>(system);
+    R_SUCCEED();
+}
+
+} // namespace Service::AM

src/core/hle/service/am/service/system_process_common_functions.h

@@ -0,0 +1,23 @@
+// SPDX-FileCopyrightText: Copyright 2026 citron Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/hle/service/cmif_types.h"
+#include "core/hle/service/service.h"
+
+namespace Service::AM {
+
+class IApplicationObserver;
+
+class ISystemProcessCommonFunctions final
+    : public ServiceFramework<ISystemProcessCommonFunctions> {
+public:
+    explicit ISystemProcessCommonFunctions(Core::System& system_);
+    ~ISystemProcessCommonFunctions() override;
+
+private:
+    Result GetApplicationObserver(Out<SharedPointer<IApplicationObserver>> out_observer);
+};
+
+} // namespace Service::AM