Fix SpotBugs warnings for missing or inconsistent hashCode

Implemented proper hashCode() methods in classes overriding equals():
- Geofence: Uses ID, radius, expiration, and location coordinates.
- PropertyBase: Uses name.
- Font: Uses font properties (face, size, style) or native font hash.
- Border: Uses type, color, thickness, arc, etc.
- Style: Uses visual properties (colors, font, background).
- TarEntry: Added equals(Object) and hashCode based on header name.
- CustomFont: Uses charset and cutOffsets.
- Transform: Uses type and transformation matrix values.
- CSSBorder (and inner classes): Uses identity hash or field hashes.
- RoundBorder/RoundRectBorder: Uses identity hash (consistent with equals).
- ImageDownloadService: Uses cacheId.
- Layouts (Border, Box, Flow, Grid, Table): Use layout properties.

Author: google-labs-jules[bot]

CodenameOne/src/com/codename1/io/services/ImageDownloadService.java

@@ -934,6 +934,13 @@ public boolean equals(Object o) {
                 ((ImageDownloadService) o).cacheId.equals(cacheId);
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public int hashCode() {
+        return cacheId != null ? cacheId.hashCode() : 0;
+    }
+
     /**
      * @return the maintainAspectRatio
      */