bttfclock: performance optimisations and dynamic layout (v0.04 + v0.05)

[NoobEjby]

This PR updates Back To The Future clock to v0.05.

v0.04 – Performance

• Cache locale and Storage modules instead of re-requiring them on every draw.
• Track Bluetooth and notification status event-driven via NRF.on('connect'/'disconnect') and Bangle.on('message') instead of polling in the draw loop.
• Remove leftover debug logging and commented-out code.

v0.05 – Dynamic layout

• Scale all coordinates, font sizes and images relative to the screen size, so the watchface no longer assumes a fixed 176x176 display.
• Center the full-screen charging animation on the current screen.

Changed files

• apps/bttfclock/app.js
• apps/bttfclock/ChangeLog
• apps/bttfclock/metadata.json

[thyttan]

Thanks!