feat(kernel): Add USB devicde and keyboard/mouse support

kernel/src/Drivers/PS2/Keyboard.cpp

@@ -291,4 +291,10 @@ namespace Drivers::PS2::Keyboard {
         return g_Modifiers;
     }
 
+    void InjectKeyEvent(const KeyEvent& event) {
+        g_BufferLock.Acquire();
+        BufferPush(event);
+        g_BufferLock.Release();
+    }
+
 };

kernel/src/Drivers/PS2/Keyboard.hpp

@@ -49,4 +49,7 @@ namespace Drivers::PS2::Keyboard {
     // Modifier state query
     const ModifierState& GetModifiers();
 
+    // Inject a key event from an external source (e.g., USB HID keyboard)
+    void InjectKeyEvent(const KeyEvent& event);
+
 };

kernel/src/Drivers/PS2/Mouse.cpp

@@ -196,4 +196,21 @@ namespace Drivers::PS2::Mouse {
         g_MaxY = maxY;
     }
 
+    void InjectMouseReport(uint8_t buttons, int8_t deltaX, int8_t deltaY, int8_t scroll) {
+        g_StateLock.Acquire();
+
+        g_State.X += (int32_t)deltaX;
+        g_State.Y += (int32_t)deltaY;
+        g_State.Buttons = buttons;
+        g_State.ScrollDelta = (int32_t)scroll;
+
+        // Clamp to screen bounds
+        if (g_State.X < 0) g_State.X = 0;
+        if (g_State.Y < 0) g_State.Y = 0;
+        if (g_State.X > g_MaxX) g_State.X = g_MaxX;
+        if (g_State.Y > g_MaxY) g_State.Y = g_MaxY;
+
+        g_StateLock.Release();
+    }
+
 };

kernel/src/Drivers/PS2/Mouse.hpp

@@ -34,4 +34,7 @@ namespace Drivers::PS2::Mouse {
 
     void SetBounds(int32_t maxX, int32_t maxY);
 
+    // Inject a mouse report from an external source (e.g., USB HID mouse)
+    void InjectMouseReport(uint8_t buttons, int8_t deltaX, int8_t deltaY, int8_t scroll);
+
 };