Add pre-commit hooks for linting and formatting

Set up pre-commit framework with ruff (backend) and ESLint/Prettier/tsc
(frontend) hooks to catch issues locally before CI. Auto-format all
frontend files with Prettier to comply with the new check.

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

frontend/src/components/admin/AdminTable.tsx

@@ -79,7 +79,10 @@ export function AdminTable<T>({
             {Array.from({ length: 5 }).map((_, i) => (
               <tr key={i}>
                 {columns.map((col) => (
-                  <td key={col.header} className={`px-4 py-3 ${col.className ?? ''}`}>
+                  <td
+                    key={col.header}
+                    className={`px-4 py-3 ${col.className ?? ''}`}
+                  >
                     <div className="h-4 bg-gray-200 dark:bg-gray-700 rounded animate-pulse" />
                   </td>
                 ))}
@@ -111,7 +114,9 @@ export function AdminTable<T>({
                 return (
                   <th
                     key={col.header}
-                    onClick={sortable ? () => handleSort(col.header) : undefined}
+                    onClick={
+                      sortable ? () => handleSort(col.header) : undefined
+                    }
                     className={`px-4 py-3 text-left text-xs font-medium text-gray-500 dark:text-gray-400 uppercase tracking-wider ${col.className ?? ''} ${sortable ? 'cursor-pointer select-none hover:text-gray-700 dark:hover:text-gray-200' : ''}`}
                   >
                     <span className="inline-flex items-center gap-1">
@@ -132,7 +137,11 @@ export function AdminTable<T>({
               <tr
                 key={keyFn(row)}
                 onClick={onRowClick ? () => onRowClick(row) : undefined}
-                className={onRowClick ? 'cursor-pointer hover:bg-gray-50 dark:hover:bg-gray-800' : ''}
+                className={
+                  onRowClick
+                    ? 'cursor-pointer hover:bg-gray-50 dark:hover:bg-gray-800'
+                    : ''
+                }
               >
                 {columns.map((col) => (
                   <td