feat(database): add repairSmokeAIAdviceIndexes function and corresponding tests

- Implemented repairSmokeAIAdviceIndexes to manage the unique index for fa_smoke_ai_advice.
- Added unit tests for the new function to ensure correct index recreation and validation.
- Updated AutoMigrate to include the new index repair function.

internal/database/smoke_index_migration.go

@@ -56,3 +56,47 @@ func repairSmokeAINextSmokeIndexes(db *gorm.DB) error {
 
 	return nil
 }
+
+func repairSmokeAIAdviceIndexes(db *gorm.DB) error {
+	if db == nil {
+		return nil
+	}
+
+	const (
+		tableName = "fa_smoke_ai_advice"
+		indexName = "uniq_smoke_ai_advice"
+	)
+
+	var rows []mysqlIndexColumn
+	if err := db.Raw(fmt.Sprintf("SHOW INDEX FROM `%s` WHERE Key_name = ?", tableName), indexName).Scan(&rows).Error; err != nil {
+		return fmt.Errorf("inspect %s: %w", indexName, err)
+	}
+
+	expected := []string{"uid", "type", "advice_date", "prompt_version"}
+	actual := make([]string, 0, len(rows))
+	for _, row := range rows {
+		actual = append(actual, row.ColumnName)
+	}
+
+	if slices.Equal(actual, expected) {
+		return nil
+	}
+
+	if len(rows) > 0 {
+		if err := db.Exec(fmt.Sprintf("ALTER TABLE `%s` DROP INDEX `%s`", tableName, indexName)).Error; err != nil {
+			return fmt.Errorf("drop %s: %w", indexName, err)
+		}
+	}
+
+	if err := db.Exec(
+		fmt.Sprintf(
+			"ALTER TABLE `%s` ADD UNIQUE KEY `%s` (`uid`,`type`,`advice_date`,`prompt_version`)",
+			tableName,
+			indexName,
+		),
+	).Error; err != nil {
+		return fmt.Errorf("create %s: %w", indexName, err)
+	}
+
+	return nil
+}