Migrate database schema to modern types and improve string handling

src/migration/0022_migrate_text_columns.sql

@@ -0,0 +1,57 @@
+-- Migrates legacy text columns to varchar(3000), which should be big enough to store really long NPC paths
+-- Also organized K_NPCPOS table
+
+CREATE TABLE [dbo].[K_NPCPOS_TMP] (
+  [ZoneID] [smallint] NOT NULL,
+  [NpcID] [int] NOT NULL,
+  [ActType] [tinyint] NOT NULL,
+  [RegenType] [tinyint] NULL,
+  [DungeonFamily] [tinyint] NULL,
+  [SpecialType] [tinyint] NULL,
+  [TrapNumber] [tinyint] NULL,
+  [LeftX] [int] NOT NULL,
+  [TopZ] [int] NOT NULL,
+  [RightX] [int] NOT NULL,
+  [BottomZ] [int] NOT NULL,
+  [LimitMinX] [int] NULL,
+  [LimitMinZ] [int] NULL,
+  [LimitMaxX] [int] NULL,
+  [LimitMaxZ] [int] NULL,
+  [NumNPC] [tinyint] NOT NULL,
+  [RegTime] [smallint] NOT NULL,
+  [DotCnt] [tinyint] NOT NULL,
+  [path] [varchar](3000) NULL -- Changed from ntext to varchar(3000)
+);
+
+INSERT INTO [dbo].[K_NPCPOS_TMP] (
+  [ZoneID], [NpcID], [ActType], [RegenType], [DungeonFamily], [SpecialType], [TrapNumber],
+  [LeftX], [TopZ], [RightX], [BottomZ], [LimitMinX], [LimitMinZ], [LimitMaxX], [LimitMaxZ],
+  [NumNPC], [RegTime], [DotCnt], [path]
+)
+SELECT
+  [ZoneID],
+  [NpcID],
+  [ActType],
+  [RegenType],
+  [DungeonFamily],
+  [SpecialType],
+  [TrapNumber],
+  [LeftX],
+  [TopZ],
+  [RightX],
+  [BottomZ],
+  [LimitMinX],
+  [LimitMinZ],
+  [LimitMaxX],
+  [LimitMaxZ],
+  [NumNPC],
+  [RegTime],
+  [DotCnt],
+  CAST([path] AS varchar(3000)) -- Convert ntext to varchar
+FROM [dbo].[K_NPCPOS];
+
+DROP TABLE [dbo].[K_NPCPOS];
+EXEC sp_rename 'dbo.K_NPCPOS_TMP', 'K_NPCPOS';
+
+-- Drop unused text column
+ALTER TABLE [dbo].[K_NPC] DROP COLUMN [Obs];