Feature(ThinkPad - Fan & Thermal Control): Add configurable status colors and translation improvements

[Piero-93]

New features

Better dynamic visual feedback for the fan status in the bar widget by:

• Coloring the widget capsule based on the current fan mode
• User can choose the color for the Fan off (Level 0), Fan active (forced speed) and Automatic modes
  from the theme palette
• Each mode can also be set to a neutral (no-color) option to match the rest of the bar
• The manual override panel highlights the selected level using the same colors

Code quality

• Wired the bar widget to actually read the color settings (colors were previously hardcoded)
• Added a reusable color-picker component shared across the three color settings
• Added/improved Italian and English translations, and localized the remaining user-facing string
• Fixed several QML warnings in the settings view