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/pages/ReceivedInvoices.jsx

@@ -369,7 +369,7 @@ export default function ReceivedInvoicesProps({ statsMonth, statsYear, uploadOpe
   const renderKpi = () => {
     if (!hasLoadedOnce.current && statsLoading) {
       return (
-        <div className="dash-kpi-grid dash-kpi-4" style={{ marginBottom: '1.5rem' }}>
+        <div className="dash-kpi-grid dash-kpi-4 mb-6">
           {[0, 1, 2, 3].map(i => (
             <div key={i} className="admin-stat-card">
               <div className="admin-skeleton-line" style={{ width: '60%', height: '11px', marginBottom: '0.5rem' }} />
@@ -456,7 +456,7 @@ export default function ReceivedInvoicesProps({ statsMonth, statsYear, uploadOpe
         transition={{ duration: 0.4, delay: 0.15 }}
       >
         <div className="admin-card-body">
-          <div className="admin-search-bar" style={{ marginBottom: '1rem' }}>
+          <div className="admin-search-bar mb-4">
             <input
               type="text"
               value={search}
@@ -549,7 +549,7 @@ export default function ReceivedInvoicesProps({ statsMonth, statsYear, uploadOpe
                       </td>
                       <td className="admin-mono">{formatDate(inv.issue_date)}</td>
                       <td className="admin-mono">{formatDate(inv.due_date)}</td>
-                      <td className="admin-mono" style={{ textAlign: 'right', fontWeight: 500 }}>
+                      <td className="admin-mono text-right fw-500">
                         {formatCurrency(inv.amount, inv.currency)}
                       </td>
                       <td>
@@ -615,7 +615,7 @@ export default function ReceivedInvoicesProps({ statsMonth, statsYear, uploadOpe
                 <h2 className="admin-modal-title">Nahrát přijaté faktury</h2>
               </div>
               <div className="admin-modal-body">
-              <div style={{ marginBottom: '1rem' }}>
+              <div className="mb-4">
                 <input
                   ref={fileInputRef}
                   type="file"