Fix extraneous blank lines in mcp logs output

Skip empty lines from the scanner that result from double newlines
(application slog trailing newline + container runtime newline).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/agent/logs.go

@@ -63,8 +63,12 @@ func (a *Agent) Logs(req *mcpv1.LogsRequest, stream mcpv1.McpAgentService_LogsSe
 
 	scanner := bufio.NewScanner(pr)
 	for scanner.Scan() {
+		line := scanner.Bytes()
+		if len(line) == 0 {
+			continue
+		}
 		if err := stream.Send(&mcpv1.LogsResponse{
-			Data: append(scanner.Bytes(), '\n'),
+			Data: append(line, '\n'),
 		}); err != nil {
 			_ = cmd.Process.Kill()
 			return err