touch: inject touches from spiceapi to native touch hooks (#824)

## Link to GitHub Issue or related Pull Request, if one exists
Fixes #814

## Description of change
Touches via the API wasn't being delivered to native touch hook;
implement this, which closes the last gap we have vs. wintouchemu.

While we're here, implement popn subscreen support for companion as
well.

## Testing
Tested for iidx/sdvx/popn

src/spice2x/api/modules/touch.h

@@ -1,8 +1,12 @@
 #pragma once
 
+#include <cstdint>
+#include <mutex>
+#include <optional>
 #include <vector>
 #include "api/module.h"
 #include "api/request.h"
+#include "touch/touch.h"
 
 namespace api::modules {
 
@@ -13,11 +17,21 @@ namespace api::modules {
     private:
         bool is_sdvx;
         bool is_tdj_fhd;
+        bool use_native;
+        std::mutex native_touch_mutex;
+        std::optional<uint32_t> native_touch_id;
+
+        // resolution the API/companion sends native touch coordinates in (after errata);
+        // used to normalize before mapping into the native injection window
+        int native_canvas_w;
+        int native_canvas_h;
 
         // function definitions
         void read(Request &req, Response &res);
         void write(Request &req, Response &res);
         void write_reset(Request &req, Response &res);
+        void write_native(const std::vector<TouchPoint> &touch_points);
+        void write_reset_native(const std::vector<DWORD> &touch_point_ids);
         void apply_touch_errata(int &x, int &y);
 
     };