fix: support Claude Code MCP protocol version

internal/mcpserver/server.go

@@ -34,6 +34,7 @@ const (
 
 var supportedProtocolVersions = []string{
 	"2025-03-26",
+	"2024-11-05",
 }
 
 type MailService interface {

internal/mcpserver/server_test.go

@@ -287,6 +287,60 @@ func TestRunnerRunWritesToolManifestAndHandlesRequests(t *testing.T) {
 	}
 }
 
+func TestRunnerRunAcceptsClaudeCodeProtocolVersion(t *testing.T) {
+	store := &storeStub{
+		credential: secretstore.Credential{
+			Host:     "imap.example.com",
+			Username: "alice",
+			Password: "secret",
+		},
+	}
+	input := bytes.NewBufferString("{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"initialize\",\"params\":{\"protocolVersion\":\"2024-11-05\",\"capabilities\":{},\"clientInfo\":{\"name\":\"claude-code\",\"version\":\"1.0.0\"}}}\n")
+	output := &bytes.Buffer{}
+	runner := NewRunner(New(store, serviceStub{
+		listMailboxes: func(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error) {
+			t.Fatal("ListMailboxes should not be called")
+			return nil, nil
+		},
+		listMessages: func(context.Context, secretstore.Credential, string, int) ([]imapclient.MessageSummary, error) {
+			t.Fatal("ListMessages should not be called")
+			return nil, nil
+		},
+		getMessage: func(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error) {
+			t.Fatal("GetMessage should not be called")
+			return imapclient.Message{}, nil
+		},
+	}), input, output, &bytes.Buffer{})
+
+	if err := runner.Run(context.Background()); err != nil {
+		t.Fatalf("Run returned error: %v", err)
+	}
+
+	var response struct {
+		JSONRPC string `json:"jsonrpc"`
+		ID      int    `json:"id"`
+		Result  struct {
+			ProtocolVersion string `json:"protocolVersion"`
+		} `json:"result"`
+		Error *struct {
+			Code    int    `json:"code"`
+			Message string `json:"message"`
+		} `json:"error"`
+	}
+	if err := json.NewDecoder(output).Decode(&response); err != nil {
+		t.Fatalf("failed to decode initialize response: %v", err)
+	}
+	if response.Error != nil {
+		t.Fatalf("expected initialize to succeed, got error %#v", response.Error)
+	}
+	if response.JSONRPC != "2.0" || response.ID != 1 {
+		t.Fatalf("unexpected response envelope: %#v", response)
+	}
+	if response.Result.ProtocolVersion != "2024-11-05" {
+		t.Fatalf("expected negotiated protocol version 2024-11-05, got %#v", response.Result)
+	}
+}
+
 func TestRunnerRunReturnsFriendlyMissingCredentialError(t *testing.T) {
 	store := &storeStub{
 		loadErr: kwallet.ErrCredentialNotFound,