refactor: CSS utility tridy + slouceni badge souboru

- pridano 20 utility trid (flex-1, mb-2, text-right, fw-500, admin-spinner-sm, atd.)
- nahrazeno ~100 opakovanych inline stylu ve 39 JSX souborech
- slouceno leave.css, orders.css, projects.css do admin.css (status badges)
- bundle size: 228.91 -> 228.43 kB (-0.48 kB)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/admin/components/OfferItemsSection.jsx

@@ -25,7 +25,7 @@ export default function OfferItemsSection({
       animate={{ opacity: 1, y: 0 }}
       transition={{ duration: 0.4, delay: 0.2 }}
     >
-      <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: '1rem' }}>
+      <div className="flex-between mb-4">
         <div>
           <h3 className="admin-card-title" style={{ margin: 0 }}>Položky</h3>
           {itemsError && <span className="admin-form-error">{itemsError}</span>}
@@ -49,7 +49,7 @@ export default function OfferItemsSection({
                         className="offers-template-menu-item"
                         onClick={() => addItemFromTemplate(t)}
                       >
-                        <div style={{ fontWeight: 500 }}>{t.name}</div>
+                        <div className="fw-500">{t.name}</div>
                         {t.default_price > 0 && (
                           <div style={{ fontSize: '0.75rem', color: 'var(--text-tertiary)' }}>
                             {Number(t.default_price).toFixed(2)}