feat: introduced a token-based theming system across the UI

* feat: added themes system

* feat: smart sidebar auto-hide for files/diff tabs + lower files sidebar threshold

* feat: added Checkbox component and update theming

- Add reusable Checkbox component for toggles across UI
- Replace several inputs with Checkbox in settings and commands panels
- Add DiffIcon and apply surface/border theming to key UI areas

* feat: Add convert-vscode-theme.cjs to convert VS Code themes to OpenChamber format

* refactor: remove unused permission logic from ChatInput

- Remove unused permission rules parsing logic from ChatInput
- Memoize renderTheme in DiffWorkerProvider to avoid unnecessary recalculations
- Remove forceOpaque helper in vscode theme adapter

* fix: guard VSCode theme loading in MarkdownRenderer

* feat: add custom user themes loading and reload

- Load user themes from ~/.config/openchamber/themes at runtime
- Expose /api/config/themes to fetch custom themes
- Allow theme reloading from Settings → Theme → Reload themes in the UI

packages/ui/src/components/views/git/HistoryCommitRow.tsx

@@ -33,13 +33,13 @@ function formatCommitDate(date: string) {
 function getChangeTypeColor(changeType: string) {
   switch (changeType) {
     case 'A':
-      return 'text-emerald-500';
+      return 'text-[var(--status-success)]';
     case 'D':
-      return 'text-red-500';
+      return 'text-[var(--status-error)]';
     case 'M':
-      return 'text-amber-500';
+      return 'text-[var(--status-warning)]';
     case 'R':
-      return 'text-blue-500';
+      return 'text-[var(--status-info)]';
     default:
       return 'text-muted-foreground';
   }