feat(formplayer): implement dark mode support

[IamLRBA]

Pull Request Title

feat(formplayer): implement dark mode support

Description

Implements dark mode support in Formplayer that adapts to the device's system theme preference.
Formulus detects the system setting using React Native's useColorScheme hook and passes it to Formplayer as an initialization parameter. Formplayer then renders a dark theme using ODE design tokens with dark backgrounds, light text, and appropriate contrast for UI elements.

How it works

Formulus (React Native):

• Uses useColorScheme() to detect the device's dark mode preference
• Passes darkMode: boolean in formParams when initializing Formplayer

Formplayer (React Web App):

• Extracts darkMode from initialization parameters
• Creates Material-UI theme using getThemeOptions(mode) function
• Applies dark mode colors using ODE design tokens:

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Screenshots

Light Mode	Dark Mode

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Type of Change

• Bug Fix
• New Feature / Enhancement
• Refactor / Code Cleanup
• Documentation Update
• Maintenance / Chore
• Other (please specify):

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Component(s) Affected

• formulus (React Native mobile app)
• formulus-formplayer (React web app)
• synkronus (Go backend server)
• synkronus-cli (Command-line utility)
• Documentation
• DevOps / CI/CD
• Other:

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Related Issue(s)

Closes/Fixes/Resolves: Closes #11

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Testing

• Unit tests added/updated
• Integration tests added/updated
• Manually tested
• Tested on multiple platforms (if applicable)
• Not applicable

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Breaking Changes

• This PR introduces breaking changes
• This PR does NOT introduce breaking changes

If breaking changes, please describe migration steps:

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Documentation Updates

• Documentation has been updated
• Documentation update is not required

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Thank you for contributing to Open Data Ensemble (ODE)!

[IamLRBA]

For this implementation, no user configuration is required and instead theme Switching is automatic.
It follows system preference on each form initialization for a seamless transition between light and dark modes.

If perhaps in the future we might need to have a theme icon and feature to assist users who might want to toggle between the modes by themselves, we can have a discussion about that for a another PR.

[r0ssing]

Great work @IamLRBA - I love dark mode!