feat: mobilni responsivita, testy, klavesove zkratky, drag & drop, univerzalizace

- Mobile responsive CSS (touch targets 44px, iOS anti-zoom, reduced motion)
- Vitest setup s 39 testy (formatters, attendanceHelpers, useTableSort)
- Klavesove zkratky (Shift+? napoveda, Ctrl+S ulozit, navigace)
- Drag & drop pro polozky nabidek (@dnd-kit, SortableRow, useSortableList)
- Univerzalizace: odstraneni BOHA brandingu z UI, emailu, PDF
- Smazany nepotrebne soubory (deploy.sh, AUTH_SYSTEM.md, example_design, .htaccess)
- CORS konfigurovatelny pres env promennou

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

api/includes/LeaveNotification.php

@@ -1,7 +1,7 @@
 <?php
 
 /**
- * BOHA Automation - Leave Request Email Notifications
+ * Leave Request Email Notifications
  *
  * Sends email notifications when leave requests are created.
  */
@@ -66,16 +66,17 @@ class LeaveNotification
                     <td style='padding: 10px; border-bottom: 1px solid #ddd;'>" . htmlspecialchars($notes) . '</td>
                 </tr>' : '') . "
             </table>
+            " . (env('APP_URL', '') ? "
             <p style='margin-top: 20px;'>
-                <a href='https://www.boha-automation.cz/boha/leave-approval'
+                <a href='" . htmlspecialchars(env('APP_URL', '')) . "/leave-approval'
                    style='background: #de3a3a; color: #fff; padding: 10px 20px;
                           text-decoration: none; border-radius: 5px;'>
                     Přejít ke schvalování
                 </a>
-            </p>
+            </p>" : "") . "
             <hr style='margin: 30px 0; border: none; border-top: 1px solid #ddd;'>
             <p style='font-size: 12px; color: #999;'>
-                Tato zpráva byla automaticky vygenerována systémem BOHA Automation.<br>
+                Tato zpráva byla automaticky vygenerována systémem.<br>
                 Datum: " . date('d.m.Y H:i:s') . '
             </p>
         </body>