feat: Implement floors, locations, and racks management

- Added list, edit, and save functionalities for floors, locations, and racks.
- Enhanced UI with search and filter options for better usability.
- Implemented SVG upload for floor plans in the floors module.
- Added validation for required fields in the save processes.
- Improved navigation in the header to reflect new modules.
- Styled forms and tables for a consistent look and feel across modules.

app/modules/locations/list.php

@@ -0,0 +1,217 @@
+<?php
+/**
+ * app/modules/locations/list.php
+ *
+ * Übersicht aller Standorte
+ */
+
+// =========================
+// Filter einlesen
+// =========================
+$search = trim($_GET['search'] ?? '');
+
+// =========================
+// Standorte laden
+// =========================
+$where = '';
+$types = '';
+$params = [];
+
+if ($search !== '') {
+    $where = "WHERE name LIKE ? OR comment LIKE ?";
+    $types = "ss";
+    $params = ["%$search%", "%$search%"];
+}
+
+$locations = $sql->get(
+    "SELECT l.*, COUNT(b.id) AS building_count
+     FROM locations l
+     LEFT JOIN buildings b ON b.location_id = l.id
+     $where
+     GROUP BY l.id
+     ORDER BY l.name",
+    $types,
+    $params
+);
+
+?>
+
+<div class="locations-container">
+    <h1>Standorte</h1>
+
+    <!-- =========================
+         Toolbar
+         ========================= -->
+    <div class="filter-form">
+        <form method="GET" style="display: flex; gap: 10px; flex-wrap: wrap; align-items: center;">
+            <input type="hidden" name="module" value="locations">
+            <input type="hidden" name="action" value="list">
+
+            <input type="text" name="search" placeholder="Suche nach Name…"
+                value="<?php echo htmlspecialchars($search); ?>" class="search-input">
+
+            <button type="submit" class="button">Filter</button>
+            <a href="?module=locations&action=list" class="button">Reset</a>
+            <a href="?module=locations&action=edit" class="button button-primary" style="margin-left: auto;">+ Neuer Standort</a>
+        </form>
+    </div>
+
+    <!-- =========================
+         Standorte-Tabelle
+         ========================= -->
+    <?php if (!empty($locations)): ?>
+    <table class="locations-list">
+        <thead>
+            <tr>
+                <th>Name</th>
+                <th>Gebäude</th>
+                <th>Beschreibung</th>
+                <th>Aktionen</th>
+            </tr>
+        </thead>
+        <tbody>
+            <?php foreach ($locations as $location): ?>
+            <tr>
+                <td>
+                    <strong><?php echo htmlspecialchars($location['name']); ?></strong>
+                </td>
+
+                <td>
+                    <?php echo $location['building_count']; ?>
+                </td>
+
+                <td>
+                    <small><?php echo htmlspecialchars($location['comment'] ?? ''); ?></small>
+                </td>
+
+                <td class="actions">
+                    <a href="?module=locations&action=edit&id=<?php echo $location['id']; ?>" class="button button-small">Bearbeiten</a>
+                    <a href="#" class="button button-small button-danger" onclick="confirmDelete(<?php echo $location['id']; ?>)">Löschen</a>
+                </td>
+            </tr>
+            <?php endforeach; ?>
+        </tbody>
+    </table>
+
+    <?php else: ?>
+    <div class="empty-state">
+        <p>Keine Standorte gefunden.</p>
+        <p>
+            <a href="?module=locations&action=edit" class="button button-primary">
+                Ersten Standort anlegen
+            </a>
+        </p>
+    </div>
+    <?php endif; ?>
+</div>
+
+<style>
+.locations-container {
+    padding: 20px;
+    max-width: 1000px;
+    margin: 0 auto;
+}
+
+.filter-form {
+    margin: 20px 0;
+}
+
+.filter-form form {
+    display: flex;
+    gap: 10px;
+    flex-wrap: wrap;
+    align-items: center;
+}
+
+.filter-form input {
+    padding: 8px 12px;
+    border: 1px solid #ddd;
+    border-radius: 4px;
+}
+
+.search-input {
+    flex: 1;
+    min-width: 250px;
+}
+
+.locations-list {
+    width: 100%;
+    border-collapse: collapse;
+    margin: 15px 0;
+}
+
+.locations-list th {
+    background: #f5f5f5;
+    padding: 12px;
+    text-align: left;
+    border-bottom: 2px solid #ddd;
+    font-weight: bold;
+}
+
+.locations-list td {
+    padding: 12px;
+    border-bottom: 1px solid #ddd;
+}
+
+.locations-list tr:hover {
+    background: #f9f9f9;
+}
+
+.actions {
+    white-space: nowrap;
+}
+
+.button {
+    display: inline-block;
+    padding: 8px 12px;
+    background: #007bff;
+    color: white;
+    text-decoration: none;
+    border-radius: 4px;
+    border: none;
+    cursor: pointer;
+    font-size: 0.9em;
+}
+
+.button:hover {
+    background: #0056b3;
+}
+
+.button-primary {
+    background: #28a745;
+}
+
+.button-primary:hover {
+    background: #218838;
+}
+
+.button-small {
+    padding: 4px 8px;
+    font-size: 0.85em;
+}
+
+.button-danger {
+    background: #dc3545;
+}
+
+.button-danger:hover {
+    background: #c82333;
+}
+
+.empty-state {
+    text-align: center;
+    padding: 40px 20px;
+    background: #f9f9f9;
+    border: 1px solid #eee;
+    border-radius: 8px;
+}
+</style>
+
+<script>
+function confirmDelete(id) {
+    if (confirm('Diesen Standort wirklich löschen?')) {
+        // TODO: AJAX-Delete implementieren
+        alert('Löschen noch nicht implementiert');
+    }
+}
+</script>