Provides the core rendering functionality for Raxol applications with functional error handling.

This module is responsible for:

• Rendering application views into screen buffers
• Managing the rendering lifecycle
• Coordinating with the output backends

Asynchronous :render_frame casts are coalesced: casts that queue up while a frame renders are absorbed into one trailing frame, drawn straight after it from the latest dispatcher state. A cast is rendered when it is handled, never deferred behind later messages. If the dispatcher exits or does not answer before dispatcher_timeout, the frame is skipped and the engine remains alive.

REFACTORED: All try/catch blocks replaced with functional error handling patterns.