feat!: add mcp conformance test infra (#585); add SSE reconnection with retry support (#596) (#585)

Adds a comprehensive conformance test suite for the Kotlin MCP SDK,
covering core protocol operations, tool calls, elicitation, resources,
prompts, and 20 OAuth/auth scenarios

- Conformance server and client implementations
- OAuth/auth test scenarios: JWT, authorization code flow, client
credentials, PKCE, scope handling, cross-app access, client registration
- CI workflow
- Baseline file for tracking expected failures
- Shell script

fixes:
- #592
- #593
- #596


## Remaining known failures (tracked issues, will be fixed directly in
`main`)

- [x] `tools-call-with-logging`, `tools-call-with-progress`,
`tools-call-sampling`, `tools-call-elicitation`,
`elicitation-sep1034-defaults`-  see #599,
- [x] `elicitation-sep1330-enums` - #587 #600
- [x] `initialize` - #588 
- [x] `tools_call`, `auth/scope-step-up`, `auth/scope-retry-limit` -
#589
- [ ] `elicitation-sep1034-client-defaults` - #414 
- [x] `sse-retry` - #590 
- [ ] `resources-templates-read` - #591 

## Breaking Changes
from #596 
- `StreamableHttpClientTransport` and
`mcpStreamableHttp`/`mcpStreamableHttpTransport`: old constructors
accepting `Duration` timeout are now `@Deprecated` — use the new
overloads with `ReconnectionOptions` instead
- `StreamableHttpClientTransport.close()` no longer calls
`terminateSession()` automatically

## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] 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
- [x] 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-client/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/StreamableHttpClientTest.kt

@@ -1,6 +1,7 @@
 package io.modelcontextprotocol.kotlin.sdk.client
 
 import io.kotest.matchers.collections.shouldContain
+import io.kotest.matchers.shouldBe
 import io.ktor.http.ContentType
 import io.ktor.http.HttpMethod
 import io.ktor.http.HttpStatusCode
@@ -203,7 +204,31 @@ internal class StreamableHttpClientTest : AbstractStreamableHttpClientTest() {
             meta = EmptyJsonObject,
         )
 
+        client.close()
+    }
+
+    @Test
+    fun `terminateSession sends DELETE request`() = runBlocking {
+        val client = Client(
+            clientInfo = Implementation(name = "client1", version = "1.0.0"),
+            options = ClientOptions(capabilities = ClientCapabilities()),
+        )
+        val sessionId = Uuid.random().toString()
+
+        mockMcp.onInitialize(clientName = "client1", sessionId = sessionId)
+        mockMcp.handleJSONRPCRequest(
+            jsonRpcMethod = "notifications/initialized",
+            expectedSessionId = sessionId,
+            sessionId = sessionId,
+            statusCode = HttpStatusCode.Accepted,
+        )
+        mockMcp.handleSubscribeWithGet(sessionId) { emptyFlow() }
+
+        connect(client)
+
         mockMcp.mockUnsubscribeRequest(sessionId = sessionId)
+        (client.transport as StreamableHttpClientTransport).terminateSession()
+        (client.transport as StreamableHttpClientTransport).sessionId shouldBe null
 
         client.close()
     }
@@ -257,8 +282,6 @@ internal class StreamableHttpClientTest : AbstractStreamableHttpClientTest() {
             buildJsonObject {}
         }
 
-        mockMcp.mockUnsubscribeRequest(sessionId = sessionId)
-
         connect(client)
 
         delay(1.seconds)