feat: add task header highlight for visual status indication

[hannesrudolph]

Summary

I want to be able to see if my task is ready for me to switch to it's desktop

So I added this setting

That does this

Adds a Task Header Highlight toggle under Settings → UI that colors the task header based on its current state, providing an at-a-glance visual indicator when tasks need attention or are complete.

• Green (--vscode-charts-green) when a task completes (completion_result)
• Yellow (--vscode-charts-yellow) when user attention is needed (follow-up questions, tool approvals, etc.)
• Skipped for subtasks and partial/streaming messages, matching the same defensive logic used by sound notifications

CSS classes override --vscode-foreground within the highlighted header so all child text, icons, SVGs, and the context window progress bar automatically use appropriate contrasting colors.

Changes

• Add taskHeaderHighlightEnabled boolean setting to global settings schema with default false
• Wire setting through ClineProvider.ts state persistence, ExtensionStateContext, and SettingsView cached state pattern
• Add checkbox toggle in UISettings under the UI tab
• Implement dual-color highlight logic in TaskHeader.tsx using useMemo with findLastIndex to determine current task state
• Add CSS classes in index.css with !important overrides and --vscode-foreground variable scoping for full child element contrast
• Add 37 tests across TaskHeader.spec.tsx and UISettings.spec.tsx
• Add translations for all 18 locales

---

Important

Introduces task header color highlights in TaskHeader.tsx to indicate task status, with settings and tests updated accordingly.

• Behavior:
  • Adds taskHeaderHighlightEnabled setting to highlight task headers based on status: green for complete, yellow for attention needed.
  • Skips highlighting for subtasks and partial messages.
• UI Components:
  • Implements highlight logic in TaskHeader.tsx using useMemo.
  • Adds checkbox in UISettings.tsx for toggling highlight.
• State Management:
  • Updates ClineProvider.ts, SettingsView.tsx, and ExtensionStateContext.tsx to handle new setting.
• CSS:
  • Adds .task-header-highlight-green and .task-header-highlight-yellow classes in index.css.
• Tests:
  • Adds tests in TaskHeader.spec.tsx and UISettings.spec.tsx.
• Localization:
  • Adds translations for 18 locales.

^{This description was created by for b3a19a8. You can customize this summary. It will automatically update as commits are pushed.}

[roomote]

Rooviewer   See task

Re-reviewed the 2 changed files since last review. Both previously flagged issues are now resolved.

• Accessibility: Now uses hardcoded background colors (#15803d, #ca8a04) instead of theme-dependent --vscode-charts-* variables, guaranteeing WCAG AA 4.5:1 contrast
• Duplicated logic: Extracted shared lastRelevantMessage useMemo consumed by both isTaskComplete and highlightClass

Previous reviews

• 3f613fb: Review #1

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}