feat: introduce feed management for individual and professor modules across frontend and backend services.

services/protobuf/feeds.proto

@@ -13,6 +13,9 @@ message Feed {
   string created = 4;
   string updated = 5;
   bool deleted = 6;
+  string type = 7;  // "prof" or "student"
+  string user = 8;  // User ID relation
+  string user_email = 9; // User Email for filtering
 }
 
 message GetFeedRequest {