[Task] patina_boot: Implement hotkey detection for boot override

[kat-perez]

Description

Implement hotkey detection in BootOrchestrator for boot override functionality (e.g., F12 for alternate boot).

Requirements

• Detect platform-configured hotkey during boot
• If hotkey pressed, use alternate boot options from Config<BootOptions>
• Requires console input to be available

Current State

Config<BootOptions> has a hotkey field that is stored but not acted upon. The field is documented as "reserved for future boot menu functionality."

Related

• RFC: Boot Orchestration (RFC: Boot Orchestration Component #1013)
• PR: patina_boot crate ([feature/patina-boot] patina_boot: Add boot orchestration crate #1225)