feat(docs): public api kdocs (#658)

- enable rule for checking undocumented public api 
- add kdoc skill

## How Has This Been Tested?
./gradlew detekt

## Breaking Changes
none

## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update

## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [x] I have added or updated documentation as needed

---------

Co-authored-by: Konstantin Pavlov <1517853+kpavlov@users.noreply.github.com>

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/SSEServerTransport.kt

@@ -26,6 +26,8 @@ internal const val SESSION_ID_PARAM = "sessionId"
  * Server transport for SSE: this will send messages over an SSE connection and receive messages from HTTP POST requests.
  *
  * Creates a new SSE server transport, which will direct the client to POST messages to the relative or absolute URL identified by `_endpoint`.
+ *
+ * @property sessionId unique identifier for this transport session, generated randomly on creation
  */
 @OptIn(ExperimentalAtomicApi::class)
 public class SseServerTransport(private val endpoint: String, private val session: ServerSSESession) :

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/ServerSession.kt

@@ -40,6 +40,8 @@ private val logger = KotlinLogging.logger {}
 
 /**
  * Represents a server session.
+ *
+ * @property sessionId unique identifier for this session, generated randomly on creation
  */
 @Suppress("TooManyFunctions")
 public open class ServerSession(

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/StreamableHttpServerTransport.kt

@@ -71,6 +71,7 @@ private data class SessionContext(val session: ServerSSESession?, val call: Appl
  * - No session validation is performed
  *
  * @param configuration Transport configuration. See [Configuration] for available options.
+ * @property sessionId session identifier assigned after initialization, or `null` in stateless mode
  */
 @OptIn(ExperimentalUuidApi::class, ExperimentalAtomicApi::class)
 @Suppress("TooManyFunctions")
@@ -122,28 +123,16 @@ public class StreamableHttpServerTransport(private val configuration: Configurat
     )
 
     /**
-     * Configuration for managing various aspects of the StreamableHttpServerTransport.
-     *
-     * @property enableJsonResponse Determines whether the server should return JSON responses.
-     *              Defaults to `false`.
-     *
-     * @property enableDnsRebindingProtection Enables DNS rebinding protection.
-     *              Defaults to `false`.
-     *
-     * @property allowedHosts A list of hosts allowed for server communication.
-     *              Defaults to `null`, allowing all hosts.
-     *
-     * @property allowedOrigins A list of allowed origins for CORS (Cross-Origin Resource Sharing).
-     *              Defaults to `null`, allowing all origins.
-     *
-     * @property eventStore The `EventStore` instance for handling resumable events.
-     *              Defaults to `null`, disabling resumability.
-     *
-     * @property retryInterval Retry interval for event handling or reconnection attempts.
-     *              Defaults to `null`.
+     * Configuration options for [StreamableHttpServerTransport].
      *
+     * @property enableJsonResponse when `true`, returns direct JSON responses instead of SSE streams
+     * @property enableDnsRebindingProtection enables DNS rebinding protection
+     * @property allowedHosts list of hosts allowed for server communication, or `null` to allow all
+     * @property allowedOrigins list of allowed CORS origins, or `null` to allow all
+     * @property eventStore store for resumable events, or `null` to disable resumability
+     * @property retryInterval retry interval for SSE reconnection attempts
      * @property maxRequestBodySize Maximum allowed size (in bytes) for incoming request bodies.
-     *              Defaults to 4 MB (4,194,304 bytes).
+     * Defaults to 4 MB (4,194,304 bytes).
      */
     public class Configuration(
         public val enableJsonResponse: Boolean = false,