#131 Circuit breaker + retry misalignment - tasks exhaust retries during CB cooldown

PROBLEM: When circuit breaker opens, tasks fail with ProtectedCallError. With no retry_strategy (default=none), failed tasks re-queue with delay=0, burning 64 max_attempts in seconds before CB cooldown helps. CURRENT: max_attempts=64, claim_timeout=15s, retry_strategy=none, CB cooldown=60s FIX: 1) Add exponential retry_strategy (base=30s, factor=2, max=300s) 2) Increase CB cooldown to 120s FILES: api/blueprints/v1/workflows.py, /etc/highway/config.ini