feat: Add version number to homepage footer

- Create version.ts in lib folder with APP_VERSION constant
- Add version footer to HomePage
- Add CSS styling for version footer
- Starting version: 0.8.0

frontend/src/lib/version.ts

@@ -0,0 +1,14 @@
+/**
+ * Application Version
+ * 
+ * Semantic Versioning: MAJOR.MINOR.PATCH
+ * - MAJOR: Incompatible API changes
+ * - MINOR: New functionality (backward compatible)
+ * - PATCH: Bug fixes (backward compatible)
+ */
+export const APP_VERSION = "0.8.0";
+
+/**
+ * Build date - set at build time
+ */
+export const BUILD_DATE = new Date().toISOString().split('T')[0];

frontend/src/pages/HomePage.tsx

@@ -1,6 +1,7 @@
 import { FormEvent, useEffect, useState } from "react";
 import { useNavigate } from "react-router-dom";
 import { apiGet } from "../lib/api";
+import { APP_VERSION } from "../lib/version";
 import type { DashboardOverview, LookupResult } from "../lib/types";
 
 function formatDate(value: string) {
@@ -174,6 +175,11 @@ export default function HomePage() {
           <div className="empty-state">Noch keine Proben vorhanden.</div>
         )}
       </section>
+
+      {/* Version Footer */}
+      <footer className="version-footer">
+        <span>Version {APP_VERSION}</span>
+      </footer>
     </div>
   );
 }

frontend/src/styles/global.css

@@ -1564,3 +1564,16 @@ a {
     grid-template-columns: 1fr;
   }
 }
+
+/* Version Footer */
+.version-footer {
+  text-align: center;
+  padding: 24px 0;
+  color: var(--muted);
+  font-size: 0.85rem;
+  opacity: 0.7;
+}
+
+.version-footer span {
+  font-weight: 500;
+}