feat: QuickDraw color-aware pattern fills and text, CopyBits safety

QuickDraw color improvements:
- FillRect: use QDPlatform_SelectPatternColor() to respect port
  foreground/background colors instead of hardcoded black/white
- FillOval: same fix - patterns now render in port colors
- Text rendering: derive glyph foreground color from port->fgColor
  instead of pattern byte intensity (enables colored text)

Security/safety:
- CopyBits: validate source/destination offsets are non-negative before
  casting to UInt32 to prevent unsigned wraparound on misaligned bitmaps
- EventDispatcher inContent: add NULL check on whichWindow before
  dereference (race condition protection)

Cleanup:
- Remove 7 debug serial_puts/MemoryManager_CheckSuspectBlock calls from
  DragWindow hot path in EventDispatcher

Author: Kelsidavis

src/EventManager/EventDispatcher.c

@@ -298,6 +298,7 @@ Boolean HandleMouseDown(EventRecord* event)
 
         case inContent: {
             /* Click in window content */
+            if (!whichWindow) return true;  /* Safety: window may have been closed */
             EVT_LOG_DEBUG("HandleMouseDown: inContent case - whichWindow=%p\n", (void*)whichWindow);
 
             WindowPtr frontWin = FrontWindow();
@@ -345,15 +346,7 @@ Boolean HandleMouseDown(EventRecord* event)
                              (void*)whichWindow, dragBounds.top, dragBounds.left,
                              dragBounds.bottom, dragBounds.right);
 
-                extern void serial_puts(const char *str);
-                serial_puts("[EVT] ABOUT TO CALL DragWindow\n");
-                serial_puts("[EVT] DragWindow function ptr logged\n");
-
-                serial_puts("[MEM] before DragWindow\n");
-                MemoryManager_CheckSuspectBlock("before_DragWindow");
                 DragWindow(whichWindow, event->where, &dragBounds);
-                serial_puts("[MEM] after DragWindow\n");
-                MemoryManager_CheckSuspectBlock("after_DragWindow");
                 EVT_LOG_DEBUG("HandleMouseDown: DragWindow returned\n");
             } else {
                 EVT_LOG_DEBUG("HandleMouseDown: inDrag but whichWindow is NULL!\n");

src/QuickDraw/Bitmaps.c

@@ -642,10 +642,16 @@ static void CopyBitsUnscaled(const BitMap *srcBits, const BitMap *dstBits,
             for (SInt16 line = 0; line < height; line++) {
                 SInt16 srcOffsetY = (srcRect->top + line - srcBits->bounds.top);
                 SInt16 dstOffsetY = (dstRect->top + line - dstBits->bounds.top);
+                SInt16 srcOffsetX = srcRect->left - srcBits->bounds.left;
+                SInt16 dstOffsetX = dstRect->left - dstBits->bounds.left;
+
+                /* Skip lines with negative offsets to prevent unsigned wraparound */
+                if (srcOffsetY < 0 || dstOffsetY < 0 || srcOffsetX < 0 || dstOffsetX < 0) continue;
+
                 UInt32 srcStart = (UInt32)srcOffsetY * (UInt32)srcRowBytes +
-                                  (UInt32)(srcRect->left - srcBits->bounds.left) * 4u;
+                                  (UInt32)srcOffsetX * 4u;
                 UInt32 dstStart = (UInt32)dstOffsetY * (UInt32)dstRowBytes +
-                                  (UInt32)(dstRect->left - dstBits->bounds.left) * 4u;
+                                  (UInt32)dstOffsetX * 4u;
                 UInt32 copyBytes = (UInt32)width * 4u;
 
                 /* Bounds safety: if pmReserved holds buffer size, clamp copy */

src/QuickDraw/QuickDrawPlatform.c

@@ -498,18 +498,12 @@ void QDPlatform_DrawShape(GrafPtr port, GrafVerb verb, const Rect* rect,
                 }
             }
         } else if (verb == fill) {
-            /* Fill with pattern (used by FillRect) */
+            /* Fill with pattern using port foreground/background colors */
             if (pat) {
                 for (SInt32 y = rect->top; y < rect->bottom; y++) {
                     for (SInt32 x = rect->left; x < rect->right; x++) {
-                        /* Get pattern bit (8x8 repeating) */
-                        SInt32 patY = y % 8;  /* Use absolute position for desktop pattern */
-                        SInt32 patX = x % 8;
-                        UInt8 patByte = pat->pat[patY];
-                        Boolean bit = (patByte >> (7 - patX)) & 1;
-
-                        /* Use black for 1 bits, white for 0 bits */
-                        UInt32 color = bit ? pack_color(0, 0, 0) : pack_color(255, 255, 255);
+                        UInt32 color = QDPlatform_SelectPatternColor(port, pat, x, y,
+                                                                      pack_color(0, 0, 0));
                         QDPlatform_SetPixel(x + offsetX, y + offsetY, color);
                     }
                 }
@@ -579,11 +573,7 @@ void QDPlatform_DrawShape(GrafPtr port, GrafVerb verb, const Rect* rect,
 
                     UInt32 color = fallbackColor;
                     if (pat) {
-                        SInt32 patY = (verb == paint) ? ((y - rect->top) & 7) : (y & 7);
-                        SInt32 patX = (verb == paint) ? ((x - rect->left) & 7) : (x & 7);
-                        UInt8 patByte = pat->pat[patY];
-                        Boolean bit = (patByte >> (7 - patX)) & 1;
-                        color = bit ? pack_color(0, 0, 0) : pack_color(255, 255, 255);
+                        color = QDPlatform_SelectPatternColor(port, pat, x, y, fallbackColor);
                     }
 
                     QDPlatform_SetPixel(x + offsetX, y + offsetY, color);
@@ -1324,12 +1314,12 @@ void QDPlatform_DrawGlyphBitmap(GrafPtr port, Point pen,
     SInt16 destHeight = destBits->bounds.bottom - destBits->bounds.top;
     SInt16 destRowBytes = destBits->rowBytes & 0x3FFF;
 
-    /* Determine foreground color from pattern */
-    uint32_t fgColor = 0xFF000000;  /* Black default */
-    if (pattern) {
-        /* Use first byte of pattern to determine intensity */
-        uint8_t intensity = 255 - pattern->pat[0];
-        fgColor = pack_color(intensity, intensity, intensity);
+    /* Determine foreground color from port's foreground color setting */
+    uint32_t fgColor;
+    if (port) {
+        fgColor = QDPlatform_MapQDColor(port->fgColor);
+    } else {
+        fgColor = pack_color(0, 0, 0);  /* Black default */
     }
 
     /* Get framebuffer pointer */