feat(backend): update Square integration, validators, and image validation

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/internal/square/square.go

@@ -50,4 +50,4 @@ func (p *ProdClient) GetCardsOnFile(ctx context.Context, userID string) ([]CardO
 
 func (p *ProdClient) DeleteCardOnFile(ctx context.Context, cardID string) error {
 	return errors.New("square payments not yet configured — set SQUARE_ACCESS_TOKEN and SQUARE_LOCATION_ID in .env")
-}
+}

backend/internal/square/square_dev.go

@@ -14,13 +14,21 @@ import (
 
 var Client SquareClient
 
+var isTesting = os.Getenv("GO_TESTING") == "1"
+
+func mockSleep(d time.Duration) {
+	if !isTesting {
+		time.Sleep(d)
+	}
+}
+
 type MockClient struct {
-	mu          sync.RWMutex
-	cards       map[string]map[string]*CardOnFile
-	checkouts   map[string]*CheckoutResult
-	payments    map[string]*PaymentResult
-	refunds     map[string]*RefundResult
-	completed   map[string]*PaymentResult
+	mu        sync.RWMutex
+	cards     map[string]map[string]*CardOnFile
+	checkouts map[string]*CheckoutResult
+	payments  map[string]*PaymentResult
+	refunds   map[string]*RefundResult
+	completed map[string]*PaymentResult
 }
 
 type devProdClient struct{}
@@ -72,7 +80,7 @@ func NewDevClient() SquareClient {
 
 func (m *MockClient) CreatePayment(ctx context.Context, req CreatePaymentReq) (*PaymentResult, error) {
 	log.Printf("[SQUARE-MOCK] CreatePayment: amount=%d, reference=%s", req.Amount, req.ReferenceID)
-	time.Sleep(1 * time.Second)
+	mockSleep(1 * time.Second)
 
 	m.mu.Lock()
 	defer m.mu.Unlock()
@@ -110,7 +118,7 @@ func (m *MockClient) CreateCheckout(ctx context.Context, req CreateCheckoutReq)
 	m.mu.Unlock()
 
 	go func() {
-		time.Sleep(3 * time.Second)
+		mockSleep(3 * time.Second)
 
 		m.mu.Lock()
 		defer m.mu.Unlock()
@@ -122,7 +130,7 @@ func (m *MockClient) CreateCheckout(ctx context.Context, req CreateCheckoutReq)
 			tipAmount = 500
 			amount += tipAmount
 		}
-		fees := amount*175/10000 // in-person rate: 1.75%
+		fees := amount * 175 / 10000 // in-person rate: 1.75%
 
 		paymentResult := &PaymentResult{
 			ID:          paymentID,
@@ -171,7 +179,7 @@ func (m *MockClient) GetCheckout(ctx context.Context, checkoutID string) (*Payme
 
 func (m *MockClient) RefundPayment(ctx context.Context, req RefundPaymentReq) (*RefundResult, error) {
 	log.Printf("[SQUARE-MOCK] RefundPayment: payment=%s, amount=%d", req.PaymentID, req.Amount)
-	time.Sleep(1 * time.Second)
+	mockSleep(1 * time.Second)
 
 	m.mu.Lock()
 	defer m.mu.Unlock()
@@ -285,4 +293,4 @@ func (m *MockClient) DeleteCardOnFile(ctx context.Context, cardID string) error
 		}
 	}
 	return fmt.Errorf("card not found: %s", cardID)
-}
+}

backend/internal/square/square_dev_test.go

@@ -350,4 +350,4 @@ func TestDevClient_ConcurrentPayments(t *testing.T) {
 	if resultCount != 10 {
 		t.Errorf("expected 10 results, got %d", resultCount)
 	}
-}
+}

backend/internal/square/types.go

@@ -27,15 +27,15 @@ type RefundPaymentReq struct {
 }
 
 type PaymentResult struct {
-	ID           string
-	Status       string // "COMPLETED", "FAILED", "PENDING"
-	Amount       int64
-	CardBrand    string
-	CardLast4    string
-	TipAmount    int64
-	ReceiptURL   string
-	SquarePayID  string // Square's payment ID
-	Fees         int64  // processing fee in pence
+	ID          string
+	Status      string // "COMPLETED", "FAILED", "PENDING"
+	Amount      int64
+	CardBrand   string
+	CardLast4   string
+	TipAmount   int64
+	ReceiptURL  string
+	SquarePayID string // Square's payment ID
+	Fees        int64  // processing fee in pence
 }
 
 type CheckoutResult struct {
@@ -44,14 +44,14 @@ type CheckoutResult struct {
 }
 
 type CardOnFile struct {
-	ID         string
-	CardID     string // Square's card-on-file token
-	Brand      string
-	Last4      string
-	ExpMonth   int
-	ExpYear    int
+	ID          string
+	CardID      string // Square's card-on-file token
+	Brand       string
+	Last4       string
+	ExpMonth    int
+	ExpYear     int
 	Fingerprint string
-	IsDefault  bool
+	IsDefault   bool
 }
 
 type RefundResult struct {
@@ -69,4 +69,4 @@ type SquareClient interface {
 	CreateCardOnFileRaw(ctx context.Context, userID, cardNumber string, expMonth, expYear int, cvc string) (*CardOnFile, error)
 	GetCardsOnFile(ctx context.Context, userID string) ([]CardOnFile, error)
 	DeleteCardOnFile(ctx context.Context, cardID string) error
-}
+}