fix: ICO needs CLI decode, AVIF compress missing options, remove JXL output

- ICO: Sharp cannot decode ICO files. Added ImageMagick-based ICO decoder
  that extracts the largest embedded image. Added ICO to CLI_DECODED_FORMATS
  and SERVER_PREVIEW_EXTENSIONS. Removed from BROWSER_PREVIEWABLE sets.
- AVIF compress: Sharp's AVIF encoder requires effort option. Added
  formatOpts() helper that supplies effort:4 for AVIF format.
- JXL output: Docker's bundled libvips lacks the JXL encoder plugin.
  Removed JXL as a convert output target to avoid guaranteed failures.
  JXL remains fully supported as an input format.

apps/api/src/routes/tool-factory.ts

@@ -295,7 +295,6 @@ export function createToolRoute<T>(app: FastifyInstance, config: ToolRouteConfig
           "image/svg+xml",
           "image/bmp",
           "image/avif",
-          "image/x-icon",
         ]);
         let previewUrl: string | undefined;
         if (!BROWSER_PREVIEWABLE.has(result.contentType)) {

apps/api/src/routes/tools/convert.ts

@@ -16,11 +16,10 @@ const FORMAT_CONTENT_TYPES: Record<string, string> = {
   gif: "image/gif",
   heic: "image/heic",
   heif: "image/heif",
-  jxl: "image/jxl",
 };
 
 const settingsSchema = z.object({
-  format: z.enum(["jpg", "png", "webp", "avif", "tiff", "gif", "heic", "heif", "jxl"]),
+  format: z.enum(["jpg", "png", "webp", "avif", "tiff", "gif", "heic", "heif"]),
   quality: z.number().min(1).max(100).optional(),
 });