feat: Add GetClubStatistics and GetNetworkStatistics APIs with corresponding request and response messages

src/CMSMicroservice.Protobuf/Protos/networkmembership.proto

@@ -45,6 +45,11 @@ service NetworkMembershipContract
             get: "/NetworkMembership/GetHistory"
         };
     };
+    rpc GetNetworkStatistics(GetNetworkStatisticsRequest) returns (GetNetworkStatisticsResponse){
+        option (google.api.http) = {
+            get: "/NetworkMembership/GetStatistics"
+        };
+    };
 }
 
 // JoinNetwork Command
@@ -150,3 +155,46 @@ message NetworkMembershipHistoryModel
     string reason = 11;
     google.protobuf.Timestamp created = 12;
 }
+
+// GetNetworkStatistics Query
+message GetNetworkStatisticsRequest
+{
+    // Empty - returns overall network statistics
+}
+
+message GetNetworkStatisticsResponse
+{
+    int32 total_members = 1;
+    int32 active_members = 2;
+    int32 left_leg_count = 3;
+    int32 right_leg_count = 4;
+    double left_percentage = 5;
+    double right_percentage = 6;
+    double average_depth = 7;
+    int32 max_depth = 8;
+    repeated LevelDistribution level_distribution = 9;
+    repeated MonthlyGrowth monthly_growth = 10;
+    repeated TopNetworkUser top_users = 11;
+}
+
+message LevelDistribution
+{
+    int32 level = 1;
+    int32 count = 2;
+}
+
+message MonthlyGrowth
+{
+    string month = 1; // Format: "2025-11" or Persian month name
+    int32 new_members = 2;
+}
+
+message TopNetworkUser
+{
+    int32 rank = 1;
+    int64 user_id = 2;
+    string user_name = 3;
+    int32 total_children = 4;
+    int32 left_count = 5;
+    int32 right_count = 6;
+}