feat: add index type, included columns, filter, and comment support

- Add filter, index_type, included_columns, and comment fields to IndexInfo
- PostgreSQL: query pg_am for index type, use indnkeyatts to split key/included columns, retrieve index comments via obj_description()
- SQL Server: add type_desc, filter_definition, included columns via is_included_column
- MySQL: add INDEX_TYPE from information_schema.STATISTICS
- Oracle: add INDEX_TYPE from ALL_INDEXES
- DDL generation: add USING (PostgreSQL), type prefix + INCLUDE + WHERE (SQL Server), COMMENT ON INDEX (PostgreSQL)
- Frontend: update types, state mapping, SQL generation, and i18n translations

src/lib/tableStructureEditorState.ts

@@ -22,18 +22,15 @@ export function createIndexDrafts(indexes: IndexInfo[]): EditableStructureIndex[
     columns: [...index.columns],
     isUnique: index.is_unique,
     isPrimary: index.is_primary,
+    filter: index.filter ?? "",
+    indexType: index.index_type ?? "",
+    includedColumns: index.included_columns ? [...index.included_columns] : [],
+    comment: index.comment ?? "",
     original: index,
     markedForDrop: false,
   }));
 }
 
-export function splitIndexColumns(value: string): string[] {
-  return value
-    .split(/[,\s]+/g)
-    .map((part) => part.trim())
-    .filter(Boolean);
-}
-
 export function toColumnNames(columns: string[]): string {
   return columns.join(", ");
 }