String.toComponent and Component.toString() methods?

This is what I use for minimessage + string to components:

```kt
fun String.toComponent(): Component = MiniMessage.miniMessage().deserialize(this)

fun Component.toString(): String = MiniMessage.miniMessage().serialize(this)
```

Start by locating the API's Component and MiniMessage integration points; the issue provides the proposed String.toComponent and Component.toString() signatures but names no files or tests. Confirm the methods fit the existing API style, then add coverage showing MiniMessage strings and Components convert in both directions.

Written by the indexing model from the issue text.