feat(loyalty): customer PIN

Adds the 6-digit customer PIN that approves every action moving EnakPoint
or EnakCoin on the customer's request (docs/prd-point-coin.md K8, F11, Q16,
Q17, PC-301).

Migration 000093 adds the PIN columns to customers and the
customer_security_events table. PIN data is read and written only through
CustomerPinRepository, never the Customer entity, so the hash cannot reach
a customer response. Only a bcrypt hash is stored.

- /customer/pin: status, OTP (pin_setup, pin_reset), create, change,
  reset. The OTP must be for that purpose and sent to the customer's own
  number; the existing OTP validation checks neither. A new PIN is checked
  (6 digits, confirmed, not one digit, not a run up or down, not the birth
  date as DDMMYY or YYMMDD) before the OTP is spent.
- Five wrong attempts in a row lock the PIN for 30 minutes; the counter is
  incremented in one statement so attempts at the same time all count,
  and a lock that ran out starts a new series. A locked PIN is refused even
  when right. The customer is told by WhatsApp, as there is no push channel
  to customers yet; only the attempt that reached the limit alerts.
- A reset through OTP lifts the lock and holds outgoing transfers for 24
  hours; paying and exchanging still work, and a held transfer costs no
  attempt.
- VerifyPin(ctx, customer, pin, action) for the flows that follow, with
  PIN_NOT_SET, PIN_INVALID (attempts left), PIN_LOCKED and
  TRANSFER_BLOCKED (until when), which PinErrorResponse turns into
  distinct codes and statuses.
- DELETE /marketing/customers/:id/pin (loyalty managers, reason required)
  and GET /marketing/customers/:id/security-events, scoped to the
  organization.

Every PIN event is in the security log with IP and user agent. No message
or binding error contains a PIN.

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

internal/processor/customer_pin_processor_test.go

@@ -0,0 +1,36 @@
+package processor
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCheckNewPin(t *testing.T) {
+	birth := time.Date(1990, 3, 14, 0, 0, 0, 0, time.UTC)
+
+	for _, ok := range []string{"482913", "019283", "135790", "112233"} {
+		assert.NoError(t, checkNewPin(ok, ok, &birth), ok)
+	}
+	for name, c := range map[string][2]string{
+		"too short":          {"12345", "12345"},
+		"too long":           {"1234567", "1234567"},
+		"not digits":         {"12a456", "12a456"},
+		"confirmation":       {"482913", "482914"},
+		"one digit":          {"111111", "111111"},
+		"zeros":              {"000000", "000000"},
+		"run up":             {"123456", "123456"},
+		"run up from 4":      {"456789", "456789"},
+		"run down":           {"654321", "654321"},
+		"run down from 9":    {"987654", "987654"},
+		"birth date DDMMYY":  {"140390", "140390"},
+		"birth date YYMMDD":  {"900314", "900314"},
+	} {
+		err := checkNewPin(c[0], c[1], &birth)
+		assert.ErrorIs(t, err, ErrInvalidPinInput, name)
+		assert.NotContains(t, err.Error(), c[0], "%s: the message must not echo the PIN", name)
+	}
+	// Without a birth date only the other rules apply.
+	assert.NoError(t, checkNewPin("140390", "140390", nil))
+}