Preset system: Add enable/disable toggle functionality

[mbachorik]

Summary

Add ability to temporarily disable presets without removing them, similar to extensions.

Context

Extensions have enable and disable commands that toggle functionality without full removal.

Presets lack this capability - the only option is full removal.

Requirements

• Add enabled field to preset registry (may already exist)
• Add preset enable CLI command
• Add preset disable CLI command
• Skip disabled presets in resolution
• Show enabled/disabled status in preset list

Related

• Reverse parity: extensions → presets