feat: add isImageFile() static utility method

Adds a static isImageFile() method to CImage that validates if a file
path points to a loadable image by attempting to load it. Returns true
only if the image loads successfully. Memory is freed immediately after
the check via scope block.

include/hyprgraphics/image/Image.hpp

@@ -37,6 +37,8 @@ namespace Hyprgraphics {
 
         Hyprutils::Memory::CSharedPointer<CCairoSurface> cairoSurface();
 
+        static bool                                      isImageFile(const std::string& path);
+
       private:
         std::string                                      lastError, filepath, mime;
         Hyprutils::Math::Vector2D                        m_svgSize;

src/image/Image.cpp

@@ -123,3 +123,12 @@ Hyprutils::Memory::CSharedPointer<CCairoSurface> Hyprgraphics::CImage::cairoSurf
 std::string Hyprgraphics::CImage::getMime() {
     return mime;
 }
+
+bool Hyprgraphics::CImage::isImageFile(const std::string& path) {
+    bool result;
+    {
+        CImage test(path);
+        result = test.success();
+    } // test destroyed here, memory freed
+    return result;
+}