jb: option to draw debug graphics to show touch interactions (#797)

## Link to GitHub Issue or related Pull Request, if one exists
related to #697 

## Description of change
Add a new option that paints touch targets and touch points for jubeat;
gets enabled if there is a touch screen connected. This is to help
explain / debug issues when users have their touch screen issues, which
is usually due to misalignment.

Fix the touch targets being off by 1 pixel (center gap is 1px wider in
both directions).

Also, simplify the `improved` algorithm to simulate a finger and trigger
nearest-neighbor for the AC dimensions. In terms of touch performance
this is near identical to what we had before, but it allows us to draw a
nice debug overlay instead of just grids.

## Testing
Tested portrait and landscape versions of jb.

src/spice2x/games/jb/jb_touch.h

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <bitset>
+#include <cstdint>
+#include <windows.h>
+
+namespace games::jb {
+
+    // touch detection algorithm
+    enum JubeatTouchAlgorithm {
+        Legacy,
+        Improved,
+        Plus,
+        AcAccurate
+    };
+
+    // debug touch overlay mode
+    enum JubeatTouchDebugMode {
+        JbTouchDebugAuto,   // boundary boxes when a touch screen is detected, else nothing
+        JbTouchDebugNone,   // draw nothing
+        JbTouchDebugBox,    // boundary boxes
+        JbTouchDebugAll,    // boundary boxes and touch circles
+    };
+
+    // selected algorithm and debug mode (set from the launcher options)
+    extern JubeatTouchAlgorithm TOUCH_ALGORITHM;
+    extern JubeatTouchDebugMode TOUCH_DEBUG_OVERLAY;
+
+    // atomically published panel state, read by the I/O layer
+    std::bitset<16> touch_state();
+
+    // read the current touch points and refresh the panel state
+    void touch_update();
+
+    // enable/disable touch handling on game attach/detach
+    void touch_attach();
+    void touch_detach();
+
+    // whether the debug overlay should currently draw anything
+    bool touch_debug_overlay_enabled();
+
+    // draw the debug touch overlay (boundary boxes and/or touch circles per the
+    // selected mode) onto the spice touch overlay window's device context
+    void touch_draw_debug_overlay(HDC hdc);
+}