- Created billing/tasks.py with replenish_monthly_credits task
- Task runs on first day of each month at midnight
- Adds plan.included_credits to all active accounts
- Creates CreditTransaction records for audit trail
- Configured in celery.py beat_schedule
- Handles errors gracefully and logs all operations
- Updated limits endpoint to show only credits and account management limits
- Removed all operation limit references (keywords, clusters, content ideas, word count, images)
- Limits endpoint now focuses on credit usage by operation type
- Account management limits (users, sites) still shown
- Updated CREDIT_COSTS to match Phase 0 spec (flat structure)
- Added get_credit_cost() method to CreditService
- Updated check_credits() to accept operation_type and amount
- Added deduct_credits_for_operation() convenience method
- Updated AI Engine to check credits BEFORE AI call
- Updated AI Engine to deduct credits AFTER successful execution
- Added helper methods for operation type mapping and amount calculation
