Add scheduled automation task and update URL routing

- Introduced a new scheduled task for executing automation rules every 5 minutes in the Celery beat schedule.
- Updated URL routing to include a new endpoint for automation-related functionalities.
- Refactored imports in various modules to align with the new business layer structure, ensuring backward compatibility for billing models, exceptions, and services.

backend/igny8_core/business/billing/models.py

@@ -0,0 +1,75 @@
+"""
+Billing Models for Credit System
+"""
+from django.db import models
+from django.core.validators import MinValueValidator
+from igny8_core.auth.models import AccountBaseModel
+
+
+class CreditTransaction(AccountBaseModel):
+    """Track all credit transactions (additions, deductions)"""
+    TRANSACTION_TYPE_CHOICES = [
+        ('purchase', 'Purchase'),
+        ('subscription', 'Subscription Renewal'),
+        ('refund', 'Refund'),
+        ('deduction', 'Usage Deduction'),
+        ('adjustment', 'Manual Adjustment'),
+    ]
+    
+    transaction_type = models.CharField(max_length=20, choices=TRANSACTION_TYPE_CHOICES, db_index=True)
+    amount = models.IntegerField(help_text="Positive for additions, negative for deductions")
+    balance_after = models.IntegerField(help_text="Credit balance after this transaction")
+    description = models.CharField(max_length=255)
+    metadata = models.JSONField(default=dict, help_text="Additional context (AI call details, etc.)")
+    created_at = models.DateTimeField(auto_now_add=True)
+    
+    class Meta:
+        db_table = 'igny8_credit_transactions'
+        ordering = ['-created_at']
+        indexes = [
+            models.Index(fields=['account', 'transaction_type']),
+            models.Index(fields=['account', 'created_at']),
+        ]
+    
+    def __str__(self):
+        account = getattr(self, 'account', None)
+        return f"{self.get_transaction_type_display()} - {self.amount} credits - {account.name if account else 'No Account'}"
+
+
+class CreditUsageLog(AccountBaseModel):
+    """Detailed log of credit usage per AI operation"""
+    OPERATION_TYPE_CHOICES = [
+        ('clustering', 'Keyword Clustering'),
+        ('idea_generation', 'Content Ideas Generation'),
+        ('content_generation', 'Content Generation'),
+        ('image_generation', 'Image Generation'),
+        ('reparse', 'Content Reparse'),
+        ('ideas', 'Content Ideas Generation'),  # Legacy
+        ('content', 'Content Generation'),  # Legacy
+        ('images', 'Image Generation'),  # Legacy
+    ]
+    
+    operation_type = models.CharField(max_length=50, choices=OPERATION_TYPE_CHOICES, db_index=True)
+    credits_used = models.IntegerField(validators=[MinValueValidator(0)])
+    cost_usd = models.DecimalField(max_digits=10, decimal_places=4, null=True, blank=True)
+    model_used = models.CharField(max_length=100, blank=True)
+    tokens_input = models.IntegerField(null=True, blank=True, validators=[MinValueValidator(0)])
+    tokens_output = models.IntegerField(null=True, blank=True, validators=[MinValueValidator(0)])
+    related_object_type = models.CharField(max_length=50, blank=True)  # 'keyword', 'cluster', 'task'
+    related_object_id = models.IntegerField(null=True, blank=True)
+    metadata = models.JSONField(default=dict)
+    created_at = models.DateTimeField(auto_now_add=True)
+    
+    class Meta:
+        db_table = 'igny8_credit_usage_logs'
+        ordering = ['-created_at']
+        indexes = [
+            models.Index(fields=['account', 'operation_type']),
+            models.Index(fields=['account', 'created_at']),
+            models.Index(fields=['account', 'operation_type', 'created_at']),
+        ]
+    
+    def __str__(self):
+        account = getattr(self, 'account', None)
+        return f"{self.get_operation_type_display()} - {self.credits_used} credits - {account.name if account else 'No Account'}"
+