Release the operator cursor for cursor-clipping games

Games that ClipCursor / re-center via SetCursorPos while focused trap the operator's
mouse (the focus spoof makes them think they're always focused), so the operator
can't reach the overlay. The Focus subsystem now inline-hooks ClipCursor and
SetCursorPos (stdcall trampolines): while "release" is requested it forces
ClipCursor(NULL) and swallows the re-centering SetCursorPos; otherwise it passes them
through. It frees any existing clip at install and re-frees each worker tick (covers
one-time clippers and a runtime clip->release toggle).

Host: protocol v10->v11 adds HookControl::allow_cursor_clip (0 = release, the
default). The Injection panel gets a "Release operator cursor" checkbox and an F2
hotkey (InjectionPanel::toggle_cursor_release); default released, since the guest
plays via the pad so the game's clip is operator-only.

Verified: full build x64 + x86 clean; ctest x64 9/9, x86 3/3. The cursor behavior
against a real clipping game (Trails through Daybreak) needs a live injected session
to confirm; logic reviewed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

host/src/injection_panel.cpp

@@ -181,6 +181,7 @@ void InjectionPanel::inject_selected()
 	server_.set_subsystem_enabled(HookSubsys_Audio, want_audio_);
 	server_.set_subsystem_enabled(HookSubsys_Video, want_video_);
 	server_.set_subsystem_enabled(HookSubsys_Mkb, want_mkb_);
+	server_.set_cursor_clip_allowed(!release_cursor_);
 
 	const InjectResult result = inject_dll(selected_pid_, hook_dll_path());
 	if (result.status == InjectStatus::Ok)
@@ -399,6 +400,13 @@ void InjectionPanel::draw_subsystem_controls(const HookStatusView& status)
 		}
 		ImGui::PopID();
 	}
+
+	// Cursor release is a Focus sub-option for games that clip/recenter the mouse
+	// (e.g. Trails through Daybreak), which would otherwise trap the operator.
+	if (ImGui::Checkbox("Release operator cursor (free the game's clip)  [F2]", &release_cursor_))
+	{
+		server_.set_cursor_clip_allowed(!release_cursor_);
+	}
 }
 
 void InjectionPanel::draw_hook_status(bool debug_details)

host/src/injection_panel.hpp

@@ -128,6 +128,21 @@ public:
 		server_.push_mkb(ev);
 	}
 
+	// --- Cursor release (for cursor-clipping games) ----------------------------
+
+	// Toggle whether the operator's mouse is released from the game's cursor clip
+	// (bound to a hotkey in the host). Republishes to the hook immediately.
+	void toggle_cursor_release()
+	{
+		release_cursor_ = !release_cursor_;
+		server_.set_cursor_clip_allowed(!release_cursor_);
+	}
+
+	[[nodiscard]] bool cursor_released() const
+	{
+		return release_cursor_;
+	}
+
 private:
 	void refresh_targets();      // refresh both the window list and the process list
 	void refresh_processes();
@@ -159,6 +174,7 @@ private:
 	bool want_audio_ = true;
 	bool want_video_ = false; // Present-hook video path: opt-in (WGC is the default)
 	bool want_mkb_ = false;   // mouse+keyboard forwarding: opt-in
+	bool release_cursor_ = true; // free the operator's mouse from the game's clip (default)
 	bool injected_ = false;   // a hook DLL is loaded in the target
 
 	// Heartbeat liveness tracking (is the injected DLL responding?).

host/src/ipc/ipc_server.hpp

@@ -87,6 +87,16 @@ public:
 		}
 	}
 
+	// Let the game clip/position the cursor (true) or release the operator's mouse
+	// (false, the default). No-op if not started.
+	void set_cursor_clip_allowed(bool allowed)
+	{
+		if (block_ != nullptr)
+		{
+			block_->control.allow_cursor_clip.store(allowed ? 1u : 0u, std::memory_order_release);
+		}
+	}
+
 	// Drain new log lines streamed by the hook, calling `emit(const LogRecord&)`
 	// for each. No-op if not started. Header-only so the callback can stay generic.
 	template <typename F>

host/src/main.cpp

@@ -184,6 +184,10 @@ int run()
 				overlay_hidden_at = ImGui::GetTime();
 			}
 		}
+		if (ImGui::IsKeyPressed(ImGuiKey_F2, false))
+		{
+			injection.toggle_cursor_release(); // free/clip the operator's mouse for clipping games
+		}
 
 		if (show_overlay)
 		{

host/src/ui/app_chrome.cpp

@@ -104,6 +104,7 @@ float draw_main_menu_bar(UiState& ui, const FrameStats& stats)
 	if (ImGui::BeginMenu("Help"))
 	{
 		ImGui::TextDisabled("F1   hide/show this overlay");
+		ImGui::TextDisabled("F2   release/clip the operator cursor");
 		ImGui::TextDisabled("Esc  quit");
 		ImGui::Separator();
 		ImGui::TextDisabled("This window is what Remote Play");