Fix credit system: Add developer/system account bypass for credit checks

- CreditService.check_credits() now bypasses for:
  1. System accounts (aws-admin, default-account, default)
  2. Developer/admin users (if user provided)
  3. Accounts with developer users (fallback for Celery tasks)
- Updated check_credits_legacy() with same bypass logic
- AIEngine credit check now uses updated CreditService
- Fixes 52 console errors caused by credit checks blocking developers
- Developers can now use AI functions without credit restrictions

backend/igny8_core/ai/engine.py

@@ -193,6 +193,7 @@ class AIEngine:
             self.tracker.update("PREP", 25, prep_message, meta=self.step_tracker.get_meta())
             
             # Phase 2.5: CREDIT CHECK - Check credits before AI call (25%)
+            # Bypass for system accounts and developers (handled in CreditService)
             if self.account:
                 try:
                     from igny8_core.modules.billing.services import CreditService
@@ -204,8 +205,9 @@ class AIEngine:
                     # Calculate estimated cost
                     estimated_amount = self._get_estimated_amount(function_name, data, payload)
                     
-                    # Check credits BEFORE AI call
-                    CreditService.check_credits(self.account, operation_type, estimated_amount)
+                    # Check credits BEFORE AI call (CreditService handles developer/system account bypass)
+                    # Note: user=None for Celery tasks, but CreditService checks account.is_system_account() and developer users
+                    CreditService.check_credits(self.account, operation_type, estimated_amount, user=None)
                     
                     logger.info(f"[AIEngine] Credit check passed: {operation_type}, estimated amount: {estimated_amount}")
                 except InsufficientCreditsError as e: