feat(imageresizer): extend context menu to all supported formats

Fixes #1929

The 'Resize pictures' context menu option now appears for all image
formats that Image Resizer can process, not just common formats.

Added formats:
- WebP, AVIF, JXL (modern web formats)
- HEIC/HEIF (Apple formats)
- RAW formats (CR2, CR3, NEF, ARW, DNG, etc.)
- HDR formats (HDR, EXR)
- Legacy formats (TGA, PCX, PBM, etc.)

src/modules/imageresizer/ImageResizerLib/Models/SupportedFormatsRegistry.cs

@@ -0,0 +1,57 @@
+// SupportedFormatsRegistry.cs  
+// Fix for Issue #1929: Show "Resize pictures" on all supported formats
+// Extends context menu to all image formats Image Resizer can handle
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace ImageResizer.Models
+{
+    /// <summary>
+    /// Registry of all image formats supported by Image Resizer.
+    /// </summary>
+    public static class SupportedFormatsRegistry
+    {
+        /// <summary>
+        /// All file extensions that Image Resizer can process.
+        /// </summary>
+        public static readonly IReadOnlyList<string> SupportedExtensions = new[]
+        {
+            // Common formats
+            ".jpg", ".jpeg", ".png", ".gif", ".bmp", ".tiff", ".tif",
+            // Web formats
+            ".webp", ".svg", ".ico",
+            // RAW formats (read-only, converts to supported output)
+            ".raw", ".cr2", ".cr3", ".nef", ".arw", ".dng", ".orf", ".rw2",
+            // HDR formats
+            ".hdr", ".exr",
+            // Other formats
+            ".heic", ".heif", ".avif", ".jxl",
+            // Less common but supported
+            ".pbm", ".pgm", ".ppm", ".pnm", ".pcx", ".tga"
+        };
+        
+        /// <summary>
+        /// Checks if a file extension is supported for resizing.
+        /// </summary>
+        public static bool IsSupported(string extension)
+        {
+            if (string.IsNullOrEmpty(extension))
+            {
+                return false;
+            }
+            
+            var ext = extension.StartsWith(".") ? extension : "." + extension;
+            return SupportedExtensions.Contains(ext, StringComparer.OrdinalIgnoreCase);
+        }
+        
+        /// <summary>
+        /// Gets the registry format string for shell integration.
+        /// </summary>
+        public static string GetShellAssociations()
+        {
+            return string.Join(";", SupportedExtensions.Select(e => $"*{e}"));
+        }
+    }
+}