Skyveil Cloudlands Pass 6

Adds lightweight white surface mist particles to Skyveil cloud blocks.
Adds charged rain clouds:
- rare darker storm-cloud block generated inside rain cloud masses
- glows temporarily while active
- random storm pulses during thunderstorms by default
- invisible 5-block electric field while active
- boosts nearby redstone dust and sends neighbor updates in the field
- direct redstone signal from the active cloud block
- command: /skyveilcloudlands pulse_charged_near <radius>

The electric field is intentionally invisible; the powered/glowing cloud block is the active indicator.
Remote power is conservative: it boosts redstone dust in range and updates nearby blocks rather than force-loading chunks or placing invisible helper blocks.
