Add OLED pitch black background option for Dark mode

[codewithtamim]

AMOLED/OLED Black Theme

Promised to customers

• Announced on social media / Matrix.

Implementation Plan

• Add to Settings as an alternative Dark Mode option.
• Research whether system dark-mode settings can or should be honored.

What it is

• Current dark mode likely uses dark gray (#121212 or similar).
• Customers want a pure black (#000000) background.

Why users care

• Battery savings on OLED/AMOLED screens
  • Black pixels = completely off → zero power consumption
  • Dark gray pixels = still lit → uses power
• Can save 3–15% battery depending on usage.