Fix: Fix Code Block Styles in Editor (Light Mode)

[DaanVersteeg]

Fixes #40 Code Blocks in the card editor displayed incorrect text colors.

Changes

frontend/src/theme.tsx

• Adjusted the code background token for light mode from #f0f0f3 to #e4e4e7 (same color as menu bar) for a slightly stronger contrast against the page background.
• Added a new semantic fg.code color token:
  • _light: '{colors.gray.700}' — dark enough to be legible on a light background
  • _dark: '{colors.gray.300}' — unchanged soft tone for dark mode

frontend/src/components/commonUI/RichText/RichText.styles.css

• Replaced the hardcoded color: #d4d4d4 on pre blocks (a light gray that was invisible in light mode) with color: var(--chakra-colors-fg-code), which now correctly resolves per theme.
• Added the same color: var(--chakra-colors-fg-code) to inline code elements, which previously had no explicit foreground color at all.

Root cause

The pre block had a hardcoded color (#d4d4d4) that only worked in dark mode. In light mode this rendered near-white text on a light background, making code essentially invisible. Inline code blocks had no foreground color set at all, so they also fell through to an unreadable default.