fix(database): V3 migration — convert UUID columns from BINARY(16) to native uuid type

Hibernate ORM 7 maps java.util.UUID to MariaDB's native uuid type, but the
V1 baseline created elytra_players.playerId and game_results.player_id as
BINARY(16). This caused two runtime errors:
- hbm2ddl=update tried to ALTER the columns but MariaDB refused due to FK
- INSERT failed with 'Data too long' because Hibernate sends UUID as a
  36-char string, not 16-byte binary

V3 drops fk_game_results_player, converts both columns to uuid NOT NULL,
and re-adds the FK. Safe on fresh installs too (no-op if already uuid).

Author: TheMeinerLP

shared/database/src/main/resources/db/migration/V3__fix_uuid_column_types.sql

@@ -0,0 +1,20 @@
+-- =============================================================================
+-- V3__fix_uuid_column_types.sql
+-- =============================================================================
+-- Hibernate ORM 7 maps java.util.UUID to MariaDB's native `uuid` type.
+-- The V1 baseline created both UUID columns as BINARY(16), causing Hibernate's
+-- hbm2ddl=update to attempt an ALTER that MariaDB rejects because the FK
+-- fk_game_results_player references elytra_players.playerId.
+--
+-- Fix: drop the FK, convert both columns, re-add the FK.
+-- Safe to run on fresh databases too: MODIFY COLUMN is a no-op when the
+-- column type is already `uuid NOT NULL`.
+-- =============================================================================
+
+ALTER TABLE game_results DROP FOREIGN KEY fk_game_results_player;
+
+ALTER TABLE elytra_players MODIFY COLUMN playerId uuid NOT NULL;
+ALTER TABLE game_results  MODIFY COLUMN player_id uuid NOT NULL;
+
+ALTER TABLE game_results ADD CONSTRAINT fk_game_results_player
+    FOREIGN KEY (player_id) REFERENCES elytra_players (playerId);