feat: update MainForm component labels for consistency and localization; enhance i18next support in translation files

frontend/src/pages/MainForm.tsx

@@ -29,20 +29,20 @@ export const MainForm = () => {
         <TextField
           required
           id="first-name"
-          label={t("first_name")}
+          label={t("first-name")}
           variant="filled"
         />
         <TextField
           required
           id="last-name"
-          label={t("last_name")}
+          label={t("last-name")}
           variant="filled"
         />
         <TextField required id="email" label={t("email")} variant="filled" />
         <TextField
           required
           id="phone-number"
-          label={t("phone_number")}
+          label={t("phone-number")}
           variant="filled"
         />
         <TextField
@@ -65,19 +65,19 @@ export const MainForm = () => {
             <TextField
               required
               id="company-name"
-              label={t("company_name")}
+              label={t("company-name")}
               variant="filled"
             />
             <TextField
               required
               id="first-name_invoice"
-              label={t("first_name")}
+              label={t("first-name")}
               variant="filled"
             />
             <TextField
               required
               id="last-name_invoice"
-              label={t("last_name")}
+              label={t("last-name")}
               variant="filled"
             />
             <TextField
@@ -89,13 +89,13 @@ export const MainForm = () => {
             <TextField
               required
               id="postal-code"
-              label={t("postal_code")}
+              label={t("postal-code")}
               variant="filled"
             />
             <TextField
               required
               id="phone-number_invoice"
-              label={t("phone_number")}
+              label={t("phone-number")}
               variant="filled"
             />
             <TextField

frontend/src/utils/i18n/locales/de/de.json

@@ -1,3 +1,12 @@
 {
-    "phone-number": "Telefonnummer"
+    "first-name": "Vorname",
+    "last-name": "Nachname",
+    "phone-number": "Telefonnummer",
+    "tickets": "Lose",
+    "invoice": "Rechnung",
+    "company-name": "Firmenname",
+    "street": "Straße + Haus Nr.",
+    "postal-code": "Plz + Stadt",
+    "email": "E-Mail",
+    "submit": "Kaufen"
 }

frontend/src/utils/i18n/locales/en/en.json

@@ -1,3 +1,12 @@
 {
-    "phone_number": "Telefonnummer"
+    "first-name": "First Name",
+    "last-name": "Last Name",
+    "phone-number": "Phone Number",
+    "tickets": "Tickets",
+    "invoice": "Invoice",
+    "company-name": "Company Name",
+    "street": "Street + House No.",
+    "postal-code": "Postal Code + City",
+    "email": "Email",
+    "submit": "Buy"
 }