complete source discovery processing lifecycle

apps/api/app/sources.py

@@ -85,10 +85,16 @@ def backoff_delay(attempt: int, base: float = 0.5, maximum: float = 30.0, jitter
     return exponential_backoff(attempt, base, maximum, jitter)
 
 def circuit_is_open(consecutive_failures: int, threshold: int = 3) -> bool:
-    return int(consecutive_failures) >= threshold
+    return int(consecutive_failures) >= max(1, int(threshold))
+
+def quota_remaining(used: int, limit: int | None) -> int | None:
+    """Return remaining quota, clamped so malformed values fail closed."""
+    if limit is None: return None
+    return max(0, int(limit) - max(0, int(used)))
 
 def quota_allowed(used: int, limit: int | None) -> bool:
-    return limit is None or (limit >= 0 and used < limit)
+    remaining = quota_remaining(used, limit)
+    return remaining is None or remaining > 0
 
 def rate_limit_delay(last_request: float | None, min_interval: float) -> float:
     if last_request is None: return 0.0