Add HTTP whole-run deadlines and context outcomes

docs/operations.md

@@ -128,6 +128,10 @@ be bounded. The existing generation timeout applies afresh to each attempt and
 does not cap retry waits or the complete invocation. The whole-run interval
 covers the engine call, including capacity waiting and repairs as supported by
 context cancellation; it excludes parsing, engine setup, and output writes.
+HTTP callers can use [`run_timeout_seconds`](api.md) to shorten their request
+context for the same engine interval. The API distinguishes an expired
+execution deadline from caller cancellation and from a provider-attempt
+timeout. A canceled capacity waiter releases its Promptkit admission state.
 
 Before increasing a limit: