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/dashboard/list.php

@@ -1,3 +1,144 @@
 <?php
+/**
+ * modules/dashboard/list.php
+ * Dashboard / Startseite - Übersicht über alle Komponenten
+ */
 
-echo '<p>Dashboard</p>';
+// =========================
+// Statistiken aus DB laden
+// =========================
+
+$stats = [
+    'devices' => $sql->single("SELECT COUNT(*) as cnt FROM devices", "", [])['cnt'] ?? 0,
+    'device_types' => $sql->single("SELECT COUNT(*) as cnt FROM device_types", "", [])['cnt'] ?? 0,
+    'racks' => $sql->single("SELECT COUNT(*) as cnt FROM racks", "", [])['cnt'] ?? 0,
+    'floors' => $sql->single("SELECT COUNT(*) as cnt FROM floors", "", [])['cnt'] ?? 0,
+    'locations' => $sql->single("SELECT COUNT(*) as cnt FROM locations", "", [])['cnt'] ?? 0,
+];
+
+// Recent devices
+$recentDevices = $sql->get(
+    "SELECT d.id, d.name, dt.name as type_name, r.name as rack_name, f.name as floor_name
+     FROM devices d
+     LEFT JOIN device_types dt ON d.device_type_id = dt.id
+     LEFT JOIN racks r ON d.rack_id = r.id
+     LEFT JOIN floors f ON r.floor_id = f.id
+     ORDER BY d.id DESC LIMIT 5",
+    "", []
+);
+
+?>
+
+<!-- Dashboard / Übersicht -->
+<div class="dashboard">
+    <h1>Dashboard</h1>
+
+    <!-- Statistik-Karten -->
+    <div class="stats-grid">
+        <div class="stat-card">
+            <h3><?php echo $stats['locations']; ?></h3>
+            <p>Standorte</p>
+            <a href="?module=floors&action=list">Verwalten →</a>
+        </div>
+
+        <div class="stat-card">
+            <h3><?php echo $stats['device_types']; ?></h3>
+            <p>Gerätetypen</p>
+            <a href="?module=device_types&action=list">Verwalten →</a>
+        </div>
+
+        <div class="stat-card">
+            <h3><?php echo $stats['devices']; ?></h3>
+            <p>Geräte</p>
+            <a href="?module=devices&action=list">Verwalten →</a>
+        </div>
+
+        <div class="stat-card">
+            <h3><?php echo $stats['racks']; ?></h3>
+            <p>Racks</p>
+            <a href="?module=racks&action=list">Verwalten →</a>
+        </div>
+    </div>
+
+    <!-- Zuletzt hinzugefügte Geräte -->
+    <h2>Zuletzt hinzugefügt</h2>
+    <?php if (!empty($recentDevices)): ?>
+    <table class="recent-devices">
+        <thead>
+            <tr>
+                <th>Name</th>
+                <th>Typ</th>
+                <th>Rack</th>
+                <th>Stockwerk</th>
+                <th></th>
+            </tr>
+        </thead>
+        <tbody>
+            <?php foreach ($recentDevices as $device): ?>
+            <tr>
+                <td><?php echo htmlspecialchars($device['name']); ?></td>
+                <td><?php echo htmlspecialchars($device['type_name'] ?? '-'); ?></td>
+                <td><?php echo htmlspecialchars($device['rack_name'] ?? '-'); ?></td>
+                <td><?php echo htmlspecialchars($device['floor_name'] ?? '-'); ?></td>
+                <td><a href="?module=devices&action=edit&id=<?php echo $device['id']; ?>">Bearbeiten</a></td>
+            </tr>
+            <?php endforeach; ?>
+        </tbody>
+    </table>
+    <?php else: ?>
+    <p><em>Noch keine Geräte vorhanden. <a href="?module=device_types&action=list">Starten Sie mit Gerätetypen</a>.</em></p>
+    <?php endif; ?>
+</div>
+
+<style>
+.stats-grid {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+    gap: 20px;
+    margin: 20px 0;
+}
+
+.stat-card {
+    border: 1px solid #ddd;
+    padding: 20px;
+    border-radius: 8px;
+    text-align: center;
+    background: #f9f9f9;
+}
+
+.stat-card h3 {
+    font-size: 2.5em;
+    margin: 0;
+    color: #333;
+}
+
+.stat-card p {
+    margin: 10px 0;
+    color: #666;
+}
+
+.stat-card a {
+    display: inline-block;
+    margin-top: 10px;
+    padding: 8px 12px;
+    background: #007bff;
+    color: white;
+    text-decoration: none;
+    border-radius: 4px;
+}
+
+.recent-devices {
+    width: 100%;
+    border-collapse: collapse;
+}
+
+.recent-devices th, .recent-devices td {
+    padding: 10px;
+    text-align: left;
+    border-bottom: 1px solid #ddd;
+}
+
+.recent-devices th {
+    background: #f0f0f0;
+}
+</style>