feat(dashboard): add up-next tile to saved dashboard layouts

src/main/resources/db/migration/V33__Up_Next_Tile.sql

@@ -0,0 +1,6 @@
+-- Core item #3: the new UP_NEXT dashboard tile, added once at the end of every saved layout. A NULL layout
+-- already shows the Frontend default, which has it. One-shot: a user who removes the tile later keeps it removed.
+UPDATE user_settings
+SET dashboard_tiles = array_append(dashboard_tiles, 'UP_NEXT:M')
+WHERE dashboard_tiles IS NOT NULL
+  AND NOT EXISTS (SELECT 1 FROM unnest(dashboard_tiles) t WHERE t LIKE 'UP_NEXT:%');