Standardised timeout handling for Falcon web applications.

[samuel-williams-shopify]

Summary:
Establish a unified timeout handling library for Falcon with consistent semantics for operation timeouts, request timeouts, and graceful degradation. This includes standard patterns for timeout propagation through nested async operations.

Why it matters:
Timeouts are critical for preventing cascading failures and resource leaks in async systems. Inconsistent timeout behavior across libraries leads to unpredictable failure modes.