[Task] patina_boot: Complete ConsoleDiscovery implementation

[kat-perez]

Description

Complete the ConsoleDiscovery component implementation. Currently a stub that locates handles but doesn't write variables.

Requirements

• Locate GOP protocol handles and create device paths
• Locate SimpleTextInput protocol handles and create device paths
• Write ConIn, ConOut, and ErrOut UEFI variables via RuntimeVariableServices
• Support multi-instance device paths for multiple consoles

Current State

The current implementation in helpers::discover_console_devices() locates handles but does not write the console variables. This is documented as a stub.

Related

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