#239 - dark mode

[zalexa19]

Fixed that dark mode bug by upgrading MUI and applying a theme :)
I am not a designer 😬 The colors should probably be tweaked.

[Copilot]

Pull request overview

This PR fixes dark mode compatibility by upgrading Material-UI (MUI) to version 7 and implementing a comprehensive theme system with proper color scheme support for both light and dark modes.

Changes:

• Upgraded MUI packages from v5 to v7 and React from v18 to v19
• Created a centralized theme configuration with dedicated color schemes for light and dark modes
• Migrated deprecated MUI component props (InputProps/InputLabelProps to slotProps)

Reviewed changes

Copilot reviewed 19 out of 20 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
client/src/theme/theme.ts	New theme configuration file defining color palettes and typography for both light and dark modes
client/src/styles/index.css	Removed CSS-based theme variables and styling now handled by MUI theme
client/src/main.tsx	Imported centralized theme instead of inline theme definition
client/src/features/trainee-profile/profile/components/TraineeProfile.tsx	Updated to use theme-aware background colors
client/src/features/trainee-profile/profile/ProfileSidebar.tsx	Replaced CSS variable with theme color token
client/src/features/trainee-profile/interactions/components/InteractionsList.tsx	Updated alternating row colors to use theme tokens
client/src/features/trainee-profile/interactions/InteractionsInfo.tsx	Removed hardcoded color prop to use theme default
client/src/features/trainee-profile/employment/EmploymentInfo.tsx	Removed hardcoded color prop to use theme default
client/src/features/trainee-profile/education/tests/TestsComponent.tsx	Removed hardcoded color prop to use theme default
client/src/features/trainee-profile/education/strikes/StrikesList.tsx	Updated alternating row colors to use theme tokens
client/src/features/trainee-profile/education/strikes/StrikesComponent.tsx	Removed hardcoded color prop to use theme default
client/src/features/trainee-profile/education/EducationInfo.tsx	Removed hardcoded color prop to use theme default
client/src/features/trainee-profile/contact/ContactInfo.tsx	Migrated TextField props from deprecated API to new slotProps syntax
client/src/features/search/components/SearchResultsList.tsx	Updated text color to use theme token for proper dark mode support
client/src/features/search/components/SearchBar.tsx	Added background color styling and migrated to slotProps API
client/src/features/search/SearchPage.tsx	Converted CSS classes to MUI Box components with theme-aware styling
client/src/features/dashboard/components/DashboardPieChart.tsx	Added type assertion to fix TypeScript error with arcLabel callback
client/src/features/dashboard/DashboardPage.tsx	Fixed JSX syntax error and added theme-aware background color
client/package.json	Upgraded MUI packages to v7, React to v19, and related type definitions

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[stasel]

Looks good. Tested on both light and dark modes. No major issues.
Ready to merge, will open separate tickets for small dark mode tweaks