chore: Rename directories from UPPERCASE to lowercase.

[nedseb]

What

Rename all top-level directories from UPPERCASE to lowercase for consistency with the other STeaMi repos.

Before	After
BASIC/	basic/
BATTERY/	battery/
BLE/	ble/
BUTTON/	button/
DEMO/	demo/
GAME/	game/
LED/	led/
ROBOT/	robot/

Why

All other STeaMi repos use lowercase directory names. UPPERCASE is unusual for a Python/MicroPython project and inconsistent with the conventions.

Blocked by

• chore: Remove redundant SENSOR/ examples. #4 — remove SENSOR/ first (no point renaming a directory that will be deleted)
• chore: Remove redundant SCREEN/ examples. #5 — remove SCREEN/ first (same reason)

How

git mv BASIC basic
git mv BATTERY battery
git mv BLE ble
git mv BUTTON button
git mv DEMO demo
git mv GAME game
git mv LED led
git mv ROBOT robot
git commit -m "chore: Rename directories to lowercase."

Note: on case-insensitive filesystems (macOS, Windows), git mv may need a two-step rename via a temporary name: git mv BASIC tmp && git mv tmp basic.

After

Update README.md to reflect the new directory names.