refactor(planet): migrate planetThemes.css hardcoded colours to CSS tokens

[adarsh-yadav1]

PR Category

• Bug Fix
• Feature
• Performance
• Tests
• Documentation

Summary

Replaces all hardcoded hex colour values in planet/css/planetThemes.css
with CSS custom property tokens from css/tokens.css, and wires
css/tokens.css into planet/index.html.

What Changed

• planet/css/planetThemes.css — 163 hardcoded hex values replaced
  with token references across dark and high-contrast themes
• planet/index.html — added import of ../css/tokens.css

Before vs After

Element	Before	After
Dark background	#303030	var(--color-background)
Dark text	#e0e0e0	var(--color-text-primary)
Dark border	#444444	var(--color-border)
Dark surface	#424242	var(--color-surface-raised)
HC background	#000080	var(--color-background)
HC text	#ffff00	var(--color-text-primary)
HC heading	#ffff00	var(--color-heading)

Screenshots

Light theme

Dark theme

High contrast theme

Test Plan

• Planet page renders correctly in light theme
• Planet page renders correctly in dark theme
• Planet page renders correctly in high-contrast theme
• Card, modal, dropdown components verified visually in browser
• Pre-existing aidebugger.test.js failure confirmed unrelated

Note

This PR depends on css/tokens.css being present, introduced in
PR #7366 . The import path ../css/tokens.css
is correct for the merged state.

Why

Part of #6606

Directly satisfies acceptance criterion 6 from the DMP 2026 project
ticket: "The Planet page uses the same token system as the main app."
All colour decisions in the Planet page now cascade from the same
tokens defined in css/tokens.css, enabling instant theme switching
without page reload.

[github-actions]

🧪 Jest Test Results

❌ Some Jest tests failed. Please check the logs and fix the issues before merging.

Coverage: Statements: 48.11% | Branches: 39.52% | Functions: 52.84% | Lines: 48.52%
Master Coverage: Statements: 48.11% | Branches: 39.52% | Functions: 52.84% | Lines: 48.52%

Note: These failures may be introduced by this PR or may already exist in the master branch.
Tip: Update your branch with the latest master and rerun tests.
If the same failures are present on master, they are likely not introduced by this PR.

Failed Tests:

aidebugger.test.js

[adarsh-yadav1]

@walterbender @sum2it This migrates all hardcoded colours in
planetThemes.css to CSS tokens and wires tokens.css into the planet
page. Visually verified in light, dark, and high-contrast themes.
Ready for review.