Add pub hours admin panel, rebuild announcements/users lists on CSS Grid

- Add a Hours admin panel (admin/hours.php, admin/hours.js) for editing
  the weekly open/close schedule and an optional per-day kitchen closing
  time, with a live preview of how it'll read on the public site
- Store hours in a new pub_hours table (inc/db.php), seeded with the
  site's existing Thu-Sat/9pm-kitchen schedule; inc/hours.php formats
  and groups it for display (day ranges, kitchen-close note, footer
  summary)
- Wire the public Visit card and both site footers (index.php, menu.php)
  to read hours from that data instead of hardcoded copy
- Rebuild the Announcements and Users admin tables onto the same CSS
  Grid list pattern already used for the Menu (admin-table-actions ->
  row-actions), and make the Announcements status toggle an in-place
  AJAX action like the menu item's (admin/index.js)
- Add the Hours tab to admin nav across all four admin pages

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

menu.php

@@ -4,9 +4,11 @@ declare(strict_types=1);
 require __DIR__ . '/config.php';
 require __DIR__ . '/inc/announcements.php';
 require __DIR__ . '/inc/menu.php';
+require __DIR__ . '/inc/hours.php';
 
 $activeAnnouncements = get_active_announcements();
 $menuCategories = get_full_menu(true); // available items only
+$hoursByDay = get_all_hours();
 $siteUrl = rtrim(SITE_URL, '/');
 ?>
 <!doctype html>
@@ -177,9 +179,9 @@ $siteUrl = rtrim(SITE_URL, '/');
         <div>
           <p class="col-title">Hours</p>
           <div class="hours-mini">
-            <span>Thu — Sat · 4:00–10:00 PM</span>
-            <span>Kitchen closes at 9 PM</span>
-            <span>Sun — Wed · Closed</span>
+            <?php foreach (hours_footer_lines($hoursByDay) as $line): ?>
+              <span><?= htmlspecialchars($line) ?></span>
+            <?php endforeach; ?>
           </div>
         </div>
         <div>