Remove web codecs usage

It was decoding transparency incorrectly (multiplication wrong?), and I'd rather not have a different code path there for the sake of it

src/client/lazy-app/Compress/index.tsx

@@ -114,7 +114,7 @@ async function decodeImage(
       }
     }
     // Otherwise fall through and try built-in decoding for a laugh.
-    return await builtinDecode(signal, blob, mimeType);
+    return await builtinDecode(signal, blob);
   } catch (err) {
     if (err instanceof Error && err.name === 'AbortError') throw err;
     console.log(err);