feat: add black colour theme

[tariknz]

• Adds setting for black theme
• Adds story for quickly testing theme changes

Untitled.mp4

[Copilot]

Pull Request Overview

This PR introduces a new black colour theme along with corresponding settings and story updates to allow quick testing of theme changes.

• Adds an optional colorPalette property to dashboard general settings.
• Updates CSS, ThemeManager component, and general settings UI to handle the new theme setting.
• Modifies story files to include theme controls alongside font size adjustments.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/types/dashboardLayout.ts	Adds an optional colorPalette property to settings
src/frontend/theme.css	Introduces CSS variables for a black-themed overlay
src/frontend/components/ThemeManager/ThemeManager.tsx	Updates theme manager to apply the new color palette
src/frontend/components/ThemeManager/ThemeManager.stories.tsx	Augments stories with theme controls alongside font size
src/frontend/components/Settings/sections/GeneralSettings.tsx	Adds dropdown and related logic for changing color theme

Comments suppressed due to low confidence (1)

src/types/dashboardLayout.ts:28

• The union type 'default' | string may unintentionally allow unsupported theme values. If only specific themes (such as 'default' and 'black') are meant to be supported, consider restricting the type to those explicit values.

  colorPalette?: 'default' | string;