fix: align backend APIs and upload flow

MessageService.Infrastructure/Migrations/MessageDbContextModelSnapshot.cs

@@ -25,6 +25,12 @@ namespace MessageService.Infrastructure.Migrations
 
             modelBuilder.Entity("MessageService.Domain.Entities.Conversation", b =>
                 {
+                    b.Property<string>("ActiveConversationKey")
+                        .ValueGeneratedOnAddOrUpdate()
+                        .HasMaxLength(96)
+                        .HasColumnType("varchar(96)")
+                        .HasComputedColumnSql("CASE WHEN `IsDeleted` = 0 THEN CONCAT(`UserId`, ':', `ChatType`, ':', `TargetId`) ELSE NULL END", true);
+
                     b.Property<Guid>("Id")
                         .ValueGeneratedOnAdd()
                         .HasColumnType("char(36)");
@@ -45,6 +51,9 @@ namespace MessageService.Infrastructure.Migrations
                         .IsRequired()
                         .HasColumnType("longtext");
 
+                    b.Property<DateTimeOffset?>("LastMessageTime")
+                        .HasColumnType("datetime(6)");
+
                     b.Property<long?>("LastReadSequenceId")
                         .HasColumnType("bigint");
 
@@ -74,8 +83,14 @@ namespace MessageService.Infrastructure.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("ActiveConversationKey")
+                        .IsUnique()
+                        .HasDatabaseName("UX_conversations_ActiveConversationKey");
+
                     b.HasIndex("UserId");
 
+                    b.HasIndex("UserId", "ChatType", "TargetId", "IsDeleted");
+
                     b.ToTable("conversations", (string)null);
                 });
 
@@ -176,6 +191,8 @@ namespace MessageService.Infrastructure.Migrations
 
                     b.HasIndex("StreamKey", "SequenceId");
 
+                    b.HasIndex("StreamKey", "MsgType", "State", "SequenceId");
+
                     b.ToTable("messages", (string)null);
                 });
 #pragma warning restore 612, 618