Suggestion: Make atlas.getSpriteAnimation sort frames by filename.

For example:

``` kotlin
fun Atlas.getSpriteAnimation(prefix: String = "", defaultTimePerFrame: TimeSpan = TimeSpan.NIL): SpriteAnimation =
SpriteAnimation(this.entries.filter { it.filename.startsWith(prefix) }***.sortedBy { it.filename }***.map { it.slice }.toFastList(), defaultTimePerFrame)

fun Atlas.getSpriteAnimation(regex: Regex, defaultTimePerFrame: TimeSpan = TimeSpan.NIL): SpriteAnimation =
SpriteAnimation(this.entries.filter { regex.matches(it.filename) }***.sortedBy { it.filename }***.map { it.slice }.toFastList(), defaultTimePerFrame)
```

Locate the Atlas.getSpriteAnimation overloads shown in the issue and inspect how matching entries are currently collected. Ensure the resulting frames are ordered by filename for both the prefix and Regex variants, then run the relevant project tests or checks to confirm the animation order.

Written by the indexing model from the issue text.