Rewrite properties in idiomatic Kotlin

[e5l]

Is your feature request related to a problem? Please describe.

There are many properties written in the typescript way:

/**
 * Retrieves the server's reported capabilities after the initialization process completes.
 *
 * @return The server's capabilities, or `null` if initialization is not yet complete.
 */
public fun getServerCapabilities(): ServerCapabilities? {
    return serverCapabilities
}

/**
 * Retrieves the server's reported version information after initialization.
 *
 * @return Information about the server's implementation, or `null` if initialization is not yet complete.
 */
public fun getServerVersion(): Implementation? {
    return serverVersion
}

Describe the solution you'd like

It would be great to rewrite such in the idiomatic kotlin properties:

```kotlin
/**
 * Retrieves the server's reported capabilities after the initialization process completes.
 *
 * @return The server's capabilities, or `null` if initialization is not yet complete.
 */
public var serverCapabilities: ServerCapabilities
    private set

/**
 * Retrieves the server's reported version information after initialization.
 *
 * @return Information about the server's implementation, or `null` if initialization is not yet complete.
 */
public var serverVersion: Implementation 
    private set