Add centered asset drawing support and refine image transformations

- Introduce `drawAssetCentered` method in `dynamicimages_image_t` for drawing assets visually centered on specified coordinates.
- Reset virtual canvas/page after image rotation in both `dynamicimages_asset_t` and `dynamicimages_image_t` to ensure consistent positioning.
- Update `machine_1` logic to use `drawAssetCentered` for improved thumb drawing and dynamic pivot alignment.
- Adjust thumb rotation calculations and positioning logic for better visual rendering.

services/nginx/app/modules/dynamicimages/traits/dynamicimages_image_t.php

@@ -160,6 +160,41 @@ trait dynamicimages_image_t
         return $this;
     }
 
+    /**
+     * Draw an asset centered around the given coordinates.
+     * This is useful for rotated layers whose bounding box changes per angle,
+     * but should visually share the same pivot point.
+     */
+    public function drawAssetCentered(dynamicimages_asset $asset, int $centerX, int $centerY, float $opacity = 1.0): dynamicimages_image_i
+    {
+        $this->assertCanvasInitialized();
+        if ($opacity < 0.0 || $opacity > 1.0) {
+            throw new \InvalidArgumentException('Opacity must be between 0.0 and 1.0');
+        }
+        $memoryImage = method_exists($asset, 'getMemoryImage') ? $asset->getMemoryImage() : null;
+        if ($memoryImage instanceof \Imagick) {
+            $layer = $memoryImage; // already a clone from asset
+        } else {
+            if (!is_readable($asset->getPath())) {
+                throw new \RuntimeException('Asset is not readable: ' . $asset->getPath());
+            }
+            $layer = new \Imagick();
+            $layer->readImage($asset->getPath());
+        }
+        $layer->setImageAlphaChannel(\Imagick::ALPHACHANNEL_SET);
+        if ($opacity < 1.0) {
+            $layer->evaluateImage(\Imagick::EVALUATE_MULTIPLY, $opacity, \Imagick::CHANNEL_ALPHA);
+        }
+        $w = (int)$layer->getImageWidth();
+        $h = (int)$layer->getImageHeight();
+        $x = (int)floor($centerX - $w / 2);
+        $y = (int)floor($centerY - $h / 2);
+        $this->image->compositeImage($layer, \Imagick::COMPOSITE_DEFAULT, $x, $y);
+        $layer->clear();
+        $layer->destroy();
+        return $this;
+    }
+
     // ===== Transformations on the temporary image object =====
     public function resize(int $width, int $height): dynamicimages_image_i
     {
@@ -192,6 +227,8 @@ trait dynamicimages_image_t
         $this->assertCanvasInitialized();
         $bg = new \ImagickPixel($background === 'transparent' ? 'transparent' : $background);
         $this->image->rotateImage($bg, $degrees);
+        // Reset virtual page so top-left is (0,0) after rotation; rotation occurs around center
+        $this->image->setImagePage(0, 0, 0, 0);
         // Update stored dimensions
         $this->canvasWidth = (int)$this->image->getImageWidth();
         $this->canvasHeight = (int)$this->image->getImageHeight();