Make completion color configurable

Would it be possible to make the color of Windsurf/Codeium's inline completions configurable instead of always gray (#808080)? If I had to guess, [this line](https://github.com/Exafunction/CodeiumJetBrains/blob/277b388cacff14f29ea10681c214b4002fe63fa3/src/main/kotlin/com/codeium/intellij/CompletionInlayRenderer.kt#L72) would need to be updated to point to a configurable color setting.