Implement comprehensive dark/light mode overhaul for admin panel

- Refactor color palette in `ui-design-spec.md` to utilize CSS variables exclusively, eliminating fixed hex values and Tailwind utility classes.
- Complete dark mode implementation in `uiStore.ts`, ensuring proper theme application via `applyTheme()` and `applyBrand()`.
- Create `admin-theme-dark-light-audit.md` to document the transition process, outlining issues with inline styles and fixed colors.
- Introduce `theme-tokens.test.ts` to enforce rules against fixed hex colors and ensure compliance with the design system.
- Update various components and styles to replace inline styles and fixed colors with CSS variables, ensuring consistent theming across light and dark modes.
- Ensure all changes maintain visual integrity in both light and dark modes, with a focus on accessibility and contrast standards.

assets/admin/pages/AppointmentCreatePage.tsx

@@ -352,7 +352,7 @@ export default function AppointmentCreatePage() {
                             border: active ? '1px solid var(--primary)' : '1px solid var(--border-2)',
                             background: active ? 'var(--primary)' : 'transparent',
                           }}>
-                            {active && <span style={{ width: 8, height: 8, background: '#fff', borderRadius: 2 }} />}
+                            {active && <span style={{ width: 8, height: 8, background: 'var(--surface)', borderRadius: 2 }} />}
                           </span>
                           {o.name}
                         </button>
@@ -378,7 +378,7 @@ export default function AppointmentCreatePage() {
                       <button type="button" aria-label={`حذف ${s.name}`} onClick={() => removeService(s.uuid)}
                         style={{
                           display: 'grid', placeItems: 'center', width: 16, height: 16, borderRadius: 999,
-                          border: 'none', cursor: 'pointer', background: 'var(--primary)', color: '#fff',
+                          border: 'none', cursor: 'pointer', background: 'var(--primary)', color: 'var(--on-primary)',
                           fontSize: 12, lineHeight: 1, fontFamily: 'inherit',
                         }}>×</button>
                     </span>
@@ -451,13 +451,13 @@ export default function AppointmentCreatePage() {
         <label style={{ display: 'inline-flex', alignItems: 'center', gap: 10, fontSize: 14, cursor: 'pointer' }}>
           <span style={{
             position: 'relative', width: 42, height: 22, borderRadius: 999, flexShrink: 0,
-            background: depositRequired ? 'var(--primary)' : '#c4c4c4', transition: 'background .2s',
+            background: depositRequired ? 'var(--primary)' : 'var(--border-2)', transition: 'background .2s',
           }}>
             <input type="checkbox" checked={depositRequired} onChange={e => setDepositRequired(e.target.checked)}
               style={{ position: 'absolute', inset: 0, width: '100%', height: '100%', margin: 0, opacity: 0, cursor: 'pointer' }} />
             <span style={{
               position: 'absolute', top: 2, insetInlineStart: depositRequired ? 22 : 2, width: 18, height: 18,
-              borderRadius: 999, background: '#fff', transition: 'inset-inline-start .2s', boxShadow: '0 1px 2px rgba(0,0,0,.2)',
+              borderRadius: 999, background: 'var(--surface)', transition: 'inset-inline-start .2s', boxShadow: '0 1px 2px rgba(0,0,0,.2)',
             }} />
           </span>
           بیعانه مورد نیاز است.