[SalesForce] embed lightning component in detail record page

You are not supposed to give same name to the apex controller's method and the function which is called on click. Also, you should pass event along with the component in the same. Please find the code below:-

Controller:-

save : function(component, event) {                
        var action = component.get("c.apexSave"); 
        action.setCallback(this, function(action) {                
           $A.get('e.force:refreshView').fire(); 
        }); 
        $A.enqueueAction(action); 
    }

Note save and apexSave.

The server-side action is also provided by the “c” value provider. This is the same value provider that provides the JavaScript controller event handler which handles the press event of the button and the init event. Because of this, you need to make sure that you do not name your Apex controller methods with the same name as your JavaScript controller methods. It’s easy to make the mistake of naming them same because it is natural to want to be consistent in naming.

Source:- Salesforce1 Lightning Components – Working with Controllers

You may use an aura handler to make sure that whether it has been refreshed successfully.

<aura:handler event="force:refreshView" action="{!c.isRefreshed}" />

Just append view text to the end of href of the anchor tag.

 <a href="{!'/one/one.app?#/sObject/'+ opp.Id + '/view'}" target="_blank">{! opp.Name }</a>