refactor(loyalty): remove what is left of tokens

Tokens are EnakCoin and no app uses the token names any more, so their
compatibility layer goes:

- GET /customer/tokens and its handler, service, processor and response
  types.
- total_tokens and tokens_history on GET /customer/wallet; last_updated
  now comes from the most recent row of either currency.
- token_used and tokens_remaining on game and spin responses, and
  sort_by=token_used on the game play list.
- TOKENS as a campaign type and reward type, with the mapping to COINS:
  migration 000092 already renamed the stored values.

The customer_tokens table and its entity stay, as cmd/wallet-migrate still
reads them, and LEGACY_TOKENS stays as the reference of the MIGRATION rows
it wrote. The docs list the removed names and their replacements.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/processor/customer_points_processor.go

@@ -22,7 +22,7 @@ func NewCustomerPointsProcessor(walletQuery *WalletQueryProcessor, gameRepo *rep
 	}
 }
 
-// The three endpoints below are the customer app's balance screens. They read the
+// The endpoints below are the customer app's balance screens. They read the
 // EnakPoint & EnakCoin wallet; customer_points and customer_tokens are no longer used
 // for balances (docs/prd-point-coin.md §9).
 
@@ -42,22 +42,6 @@ func (p *CustomerPointsProcessor) GetCustomerTotalPointsAPI(ctx context.Context,
 	}, nil
 }
 
-func (p *CustomerPointsProcessor) GetCustomerTotalTokensAPI(ctx context.Context, customerID string) (*models.GetCustomerTokensResponse, error) {
-	id, err := parseWalletCustomerID(customerID)
-	if err != nil {
-		return nil, err
-	}
-	data, err := p.walletQuery.LegacyTokens(ctx, id)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get customer tokens: %w", err)
-	}
-	return &models.GetCustomerTokensResponse{
-		Status:  "SUCCESS",
-		Message: "Customer tokens retrieved successfully.",
-		Data:    data,
-	}, nil
-}
-
 func (p *CustomerPointsProcessor) GetCustomerWalletAPI(ctx context.Context, customerID string) (*models.GetCustomerWalletResponse, error) {
 	id, err := parseWalletCustomerID(customerID)
 	if err != nil {