feat: Add manual email sending workflow and related database changes

- Implemented a new n8n workflow for manual email sending, including webhook trigger, order data fetching, email building, and sending.
- Added logic to format email content with customer and order details.
- Introduced new columns in the sales_orders table to track email sending status.
- Updated database functions to handle new rental types and email status.
- Created new RPCs for updating email status and retrieving email details for sales orders.

frontend/index.html

@@ -113,7 +113,6 @@
 
             <nav class="main-nav" aria-label="Hauptnavigation">
                 <a href="#fahrzeuge" data-i18n="navCars">Fahrzeuge</a>
-                <a href="#warum"     data-i18n="navWhy">Warum wir</a>
                 <a href="#stimmen"   data-i18n="navReviews">Stimmen</a>
                 <a href="#buchen"    data-i18n="navBook">Buchen</a>
                 <a class="btn small" href="#buchen" data-i18n="bookNow">Jetzt buchen</a>
@@ -179,37 +178,6 @@
             </div>
         </section>
 
-        <!-- Why -->
-        <section id="warum" style="background:var(--bg-elev);">
-                    <a href="/impressum" data-i18n="imprint">Impressum</a>
-                    <a href="/agb" data-i18n="terms">AGB</a>
-                    <a href="/mietbedingungen" data-i18n="rentalTerms">Mietbedingungen</a>
-                    <a href="/datenschutz" data-i18n="privacy">Datenschutz</a>
-                        <p class="eyebrow" data-i18n="whyEyebrow">Warum MC Cars</p>
-                        <h2 data-i18n="whyTitle">Keine Kompromisse zwischen Sicherheit und Fahrspaß.</h2>
-                    </div>
-                </div>
-
-                <div class="why-grid">
-                    <article class="why-card">
-                        <div class="icon">🛡</div>
-                        <h3 data-i18n="whyInsurance">Versicherungsschutz</h3>
-                        <p data-i18n="whyInsuranceText">Vollkasko mit klarem Selbstbehalt.</p>
-                    </article>
-                    <article class="why-card">
-                        <div class="icon">★</div>
-                        <h3 data-i18n="whyFleet">Premium Flotte</h3>
-                        <p data-i18n="whyFleetText">Handverlesene Performance-Modelle.</p>
-                    </article>
-                    <article class="why-card">
-                        <div class="icon">€</div>
-                        <h3 data-i18n="whyDeposit">Faire Kaution</h3>
-                        <p data-i18n="whyDepositText">Kein Überziehen. Transparente, faire Kaution ohne unnötige Belastung.</p>
-                    </article>
-                </div>
-            </div>
-        </section>
-
     <!-- Toast Notification -->
     <div id="toast" class="toast" role="status" aria-live="polite" aria-atomic="true"></div>
         <!-- Reviews -->
@@ -409,8 +377,7 @@
                 <div>
                     <h4 data-i18n="footerNav">Navigation</h4>
                     <a href="#fahrzeuge" data-i18n="navCars">Fahrzeuge</a>
-                    <a href="#warum"     data-i18n="navWhy">Warum wir</a>
-                    <a href="#buchen"    data-i18n="navBook">Buchen</a>
+                <a href="#buchen"    data-i18n="navBook">Buchen</a>
                 </div>
 
                 <div>
@@ -447,6 +414,6 @@
     <div id="toast" class="toast" role="status" aria-live="polite" aria-atomic="true"></div>
 
     <script src="config.js"></script>
-    <script type="module" src="app.js"></script>
+    <script type="module" src="app.js?v=3"></script>
 </body>
 </html>