Add RGB Hexpansion cockpit and release 0.1.5

[devnulluk]

What changed

• turn the Keepdexpansion RGB keyboard into a five-zone live traffic meter, idle scanner, special-traffic display, flight-progress bar and emergency chase
• add equivalent 14-pixel effects for the East Essex Hackspace Logo
• add independent Hexpansion enable, brightness and safe EEH Logo port controls
• honour the EEH controller’s saved slot assignment, avoid its active background driver, and never probe an unknown port
• preserve and restore the keyboard’s prior ownership, colour and pattern state
• update documentation, CI syntax coverage and metadata for version 0.1.5

Why

The attached Hexpansions should feel like parts of the radar instrument, while remaining optional and safe for a base 2024 badge or unrelated hardware.

Validation

• python -m unittest discover -s tests -v — 67 tests passing
• full Python syntax compilation
• Tildagon simulator: normal traffic demo, Hexpansion options, keyboard input regression, and explicit 14-pixel Logo driver path
• git diff --check