Add DEPOSITO transaction type and Salarios page

New TransactionType.DEPOSITO for salary deposits from n8n/Gmail flow.
New /salarios endpoint with summary. New top-level Salarios page with
DataTable and summary cards. Push notifications link to /salarios for
deposits.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/models/models.py

@@ -23,6 +23,7 @@ class RecurringFrequency(str, enum.Enum):
 class TransactionType(str, enum.Enum):
     COMPRA = "COMPRA"
     DEVOLUCION = "DEVOLUCION"
+    DEPOSITO = "DEPOSITO"
 
 
 class TransactionSource(str, enum.Enum):