feat: add notification for elicitation complete (#667)

closes #546 

## How Has This Been Tested?
unit

## Breaking Changes
none

## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] 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
- [ ] I have added or updated documentation as needed

integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/server/ClientConnectionTest.kt

@@ -7,6 +7,8 @@ import io.kotest.matchers.string.shouldNotBeBlank
 import io.modelcontextprotocol.kotlin.sdk.types.CallToolRequest
 import io.modelcontextprotocol.kotlin.sdk.types.CallToolRequestParams
 import io.modelcontextprotocol.kotlin.sdk.types.ClientCapabilities
+import io.modelcontextprotocol.kotlin.sdk.types.ElicitationCompleteNotification
+import io.modelcontextprotocol.kotlin.sdk.types.ElicitationCompleteNotificationParams
 import io.modelcontextprotocol.kotlin.sdk.types.GetPromptRequest
 import io.modelcontextprotocol.kotlin.sdk.types.GetPromptRequestParams
 import io.modelcontextprotocol.kotlin.sdk.types.ListRootsRequest
@@ -77,6 +79,8 @@ class ClientConnectionTest : AbstractServerFeaturesTest() {
         val loggingMessage = onClientNotification<LoggingMessageNotification>(Method.Defined.NotificationsMessage)
         val resourceUpdated =
             onClientNotification<ResourceUpdatedNotification>(Method.Defined.NotificationsResourcesUpdated)
+        val elicitationComplete =
+            onClientNotification<ElicitationCompleteNotification>(Method.Defined.NotificationsElicitationComplete)
 
         init {
             onClientRequest<ListRootsRequest, ListRootsResult>(Method.Defined.RootsList) {
@@ -109,6 +113,12 @@ class ClientConnectionTest : AbstractServerFeaturesTest() {
                 withClue("sendResourceUpdated() delivered wrong URI") {
                     resourceUri shouldBe "test://res"
                 }
+                withClue("sendElicitationComplete() did not deliver a notification to the client") {
+                    elicitationComplete.isCompleted shouldBe true
+                }
+                withClue("sendElicitationComplete() delivered wrong elicitationId") {
+                    elicitationComplete.await().params.elicitationId shouldBe "elicit-123"
+                }
                 capturedSessionId.shouldNotBeBlank()
             }
         }
@@ -128,6 +138,9 @@ class ClientConnectionTest : AbstractServerFeaturesTest() {
             ),
         )
         sendResourceUpdated(ResourceUpdatedNotification(ResourceUpdatedNotificationParams("test://res")))
+        sendElicitationComplete(
+            ElicitationCompleteNotification(ElicitationCompleteNotificationParams(elicitationId = "elicit-123")),
+        )
         cap.sessionId.complete(sessionId)
     }