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/lib/file-validation.ts

@@ -67,7 +67,7 @@ export interface ValidationError {
 const RAW_EXTENSIONS = new Set(["dng", "cr2", "nef", "arw", "orf", "rw2"]);
 
 /** Formats that Sharp cannot decode natively — skip dimension check. */
-const CLI_DECODED_FORMATS = new Set(["raw", "tga", "psd", "exr", "hdr"]);
+const CLI_DECODED_FORMATS = new Set(["raw", "ico", "tga", "psd", "exr", "hdr"]);
 
 /**
  * Check whether a file extension corresponds to a Camera RAW format.

apps/api/src/lib/format-decoders.ts

@@ -8,7 +8,7 @@ import { promisify } from "node:util";
 const execFileAsync = promisify(execFile);
 
 /** Formats that need external CLI tools (not decodable by Sharp). */
-const CLI_DECODED_FORMATS = new Set(["raw", "tga", "psd", "exr", "hdr"]);
+const CLI_DECODED_FORMATS = new Set(["raw", "ico", "tga", "psd", "exr", "hdr"]);
 
 export function needsCliDecode(format: string): boolean {
   return CLI_DECODED_FORMATS.has(format);
@@ -22,6 +22,8 @@ export async function decodeToSharpCompat(buffer: Buffer, format: string): Promi
   switch (format) {
     case "raw":
       return decodeRaw(buffer);
+    case "ico":
+      return decodeIco(buffer);
     case "psd":
       return decodePsd(buffer);
     case "tga":
@@ -57,6 +59,29 @@ function magickArgs(cmd: string, args: string[]): string[] {
   return cmd === "magick" ? ["convert", ...args] : args;
 }
 
+// ── ICO decoder ────────────────────────────────────────────────
+
+async function decodeIco(buffer: Buffer): Promise<Buffer> {
+  const cmd = await findMagickCmd();
+  const id = randomUUID();
+  const inputPath = join(tmpdir(), `ico-in-${id}.ico`);
+  const outputPath = join(tmpdir(), `ico-out-${id}.png`);
+
+  try {
+    await writeFile(inputPath, buffer);
+    // ICO contains multiple sizes; extract the largest by sorting
+    await execFileAsync(
+      cmd,
+      magickArgs(cmd, [`${inputPath}[-1]`, `png:${outputPath}`]),
+      { timeout: 120_000 },
+    );
+    return await readFile(outputPath);
+  } finally {
+    await rm(inputPath, { force: true }).catch(() => {});
+    await rm(outputPath, { force: true }).catch(() => {});
+  }
+}
+
 // ── RAW decoder (ImageMagick with LibRaw delegate) ─────────────
 
 async function decodeRaw(buffer: Buffer): Promise<Buffer> {

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(),
 });