Refactor payment service, fix DB session, and consolidate endpoints

- Fix critical NameError in database.py by restoring Session factory
- Refactor payment_service.py and crud.py to use shared constants.py and utils.py
- Deduplicate state mapping and input sanitization logic
- Move transaction amount calculation logic from CRUD to Router layer
- Enforce type safety in schemas using IntEnum for TransactionType/Status
- Move capture endpoint from transaction.py to payment.py (now /payments/capture)
- Update create_customer_profile signature for clarity

app/constants.py

@@ -0,0 +1,28 @@
+"""
+Constants shared across the EAMCO Authorize service.
+"""
+import enum
+
+class TransactionStatus(enum.IntEnum):
+    """Transaction status codes used throughout the payment system."""
+    APPROVED = 0
+    DECLINED = 1
+
+
+class TransactionType(enum.IntEnum):
+    """Transaction type codes for different payment operations."""
+    CHARGE = 0
+    AUTHORIZE = 1
+    CAPTURE = 2
+
+# State ID to abbreviation mapping for Authorize.net billing address
+# This maps the integer state IDs from the database to state abbreviations
+STATE_ID_TO_ABBREVIATION = {
+    0: "MA",
+    1: "RI",
+    2: "NH",
+    3: "ME",
+    4: "VT",
+    5: "CT",
+    6: "NY"
+}