feat: Add gRPC API Layer - Phase 6 Integration

Added Protobuf definitions and gRPC services for all CQ layers:

Protobuf Files (4):
- configuration.proto: 2 Commands + 3 Queries (5 RPCs)
- clubmembership.proto: 3 Commands + 3 Queries (6 RPCs)
- networkmembership.proto: 3 Commands + 3 Queries (6 RPCs)
- commission.proto: 5 Commands + 4 Queries (9 RPCs)

gRPC Services (4):
- ConfigurationService: SetConfigurationValue, Deactivate, GetByKey, GetAll, GetHistory
- ClubMembershipService: Activate, Deactivate, AssignFeature, Get, GetAll, GetHistory
- NetworkMembershipService: Join, Move, Remove, GetPosition, GetTree, GetHistory
- CommissionService: Calculate+Process+Withdraw (5 commands), Get queries (4)

Features:
- HTTP transcoding enabled via google.api.http annotations
- Auto-registration via ConfigureGrpcEndpoints
- MetaData pagination support
- Request/Response DTOs for all endpoints
- Integration with MediatR CQRS handlers

Total: 4 proto files, 4 service classes, 26 RPC endpoints
Build: ✅ Successful (0 errors)

src/CMSMicroservice.WebApi/Services/NetworkMembershipService.cs

@@ -0,0 +1,50 @@
+using CMSMicroservice.Protobuf.Protos.NetworkMembership;
+using CMSMicroservice.WebApi.Common.Services;
+using CMSMicroservice.Application.NetworkMembershipCQ.Commands.JoinNetwork;
+using CMSMicroservice.Application.NetworkMembershipCQ.Commands.MoveInNetwork;
+using CMSMicroservice.Application.NetworkMembershipCQ.Commands.RemoveFromNetwork;
+using CMSMicroservice.Application.NetworkMembershipCQ.Queries.GetUserNetworkPosition;
+using CMSMicroservice.Application.NetworkMembershipCQ.Queries.GetNetworkTree;
+using CMSMicroservice.Application.NetworkMembershipCQ.Queries.GetNetworkMembershipHistory;
+
+namespace CMSMicroservice.WebApi.Services;
+
+public class NetworkMembershipService : NetworkMembershipContract.NetworkMembershipContractBase
+{
+    private readonly IDispatchRequestToCQRS _dispatchRequestToCQRS;
+
+    public NetworkMembershipService(IDispatchRequestToCQRS dispatchRequestToCQRS)
+    {
+        _dispatchRequestToCQRS = dispatchRequestToCQRS;
+    }
+
+    public override async Task<Empty> JoinNetwork(JoinNetworkRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<JoinNetworkRequest, JoinNetworkCommand>(request, context);
+    }
+
+    public override async Task<Empty> ChangeNetworkParent(ChangeNetworkParentRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<ChangeNetworkParentRequest, MoveInNetworkCommand>(request, context);
+    }
+
+    public override async Task<Empty> RemoveFromNetwork(RemoveFromNetworkRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<RemoveFromNetworkRequest, RemoveFromNetworkCommand>(request, context);
+    }
+
+    public override async Task<GetUserNetworkResponse> GetUserNetwork(GetUserNetworkRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<GetUserNetworkRequest, GetUserNetworkPositionQuery, GetUserNetworkResponse>(request, context);
+    }
+
+    public override async Task<GetNetworkTreeResponse> GetNetworkTree(GetNetworkTreeRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<GetNetworkTreeRequest, GetNetworkTreeQuery, GetNetworkTreeResponse>(request, context);
+    }
+
+    public override async Task<GetNetworkMembershipHistoryResponse> GetNetworkMembershipHistory(GetNetworkMembershipHistoryRequest request, ServerCallContext context)
+    {
+        return await _dispatchRequestToCQRS.Handle<GetNetworkMembershipHistoryRequest, GetNetworkMembershipHistoryQuery, GetNetworkMembershipHistoryResponse>(request, context);
+    }
+}