Refactor code and improve internationalization support

- Updated import statements to remove invisible characters.
- Standardized comments to use a consistent hyphen format.
- Adjusted username validation error messages for consistency.
- Enhanced email sending functions to include language support.
- Added email internationalization configuration for dynamic translations.
- Updated calendar and federation routes to include language in user queries.
- Improved user feedback messages in German and English for clarity.

src/i18n/en.json

@@ -1,4 +1,4 @@
-{
+{
   "common": {
     "appName": "Redlight",
     "loading": "Loading...",
@@ -76,11 +76,11 @@
     "emailNotVerified": "Email not yet verified. Please check your inbox.",
     "username": "Username",
     "usernamePlaceholder": "e.g. johndoe",
-    "usernameHint": "Letters, numbers, _ and - only (3–30 chars)",
+    "usernameHint": "Letters, numbers, _ and - only (3-30 chars)",
     "displayName": "Display Name",
     "displayNamePlaceholder": "John Doe",
     "usernameTaken": "Username is already taken",
-    "usernameInvalid": "Username may only contain letters, numbers, _ and - (3–30 chars)",
+    "usernameInvalid": "Username may only contain letters, numbers, _ and - (3-30 chars)",
     "usernameRequired": "Username is required",
     "displayNameRequired": "Display name is required",
     "emailVerificationBanner": "Your email address has not been verified yet.",
@@ -394,7 +394,7 @@
     "removeRoomConfirm": "Really remove this room?",
     "roomRemoved": "Room removed",
     "roomRemoveFailed": "Could not remove room",
-    "acceptedSaved": "Invitation accepted – room saved to your dashboard!",
+    "acceptedSaved": "Invitation accepted - room saved to your dashboard!",
     "meetingId": "Meeting ID",
     "maxParticipants": "Max. participants",
     "recordingOn": "Recording enabled",
@@ -412,7 +412,7 @@
     "calendarEvent": "Calendar Invitation",
     "calendarAccepted": "Calendar event accepted and added to your calendar!",
     "localCalendarEvent": "Local Calendar Invitation",
-    "calendarLocalAccepted": "Invitation accepted – event added to your calendar!",
+    "calendarLocalAccepted": "Invitation accepted - event added to your calendar!",
     "invitationRemoved": "Invitation removed",
     "removeInvitation": "Remove invitation"
   },
@@ -475,5 +475,42 @@
     "organizer": "Organizer",
     "federatedFrom": "From remote instance",
     "joinFederatedMeeting": "Join remote meeting"
+  },
+  "email": {
+    "greeting": "Hey {name} 👋",
+    "viewInvitation": "View Invitation",
+    "invitationFooter": "Open the link above to accept or decline the invitation.",
+    "linkHint": "Or copy this link in your browser:",
+    "verify": {
+      "subject": "{appName} - Verify your email",
+      "intro": "Please verify your email address by clicking the button below:",
+      "button": "Verify Email",
+      "validity": "This link is valid for 24 hours.",
+      "footer": "If you didn't register, please ignore this email."
+    },
+    "invite": {
+      "subject": "{appName} - You've been invited",
+      "title": "You've been invited! 🎉",
+      "intro": "You have been invited to create an account on {appName}.",
+      "prompt": "Click the button below to register:",
+      "button": "Create Account",
+      "validity": "This link is valid for 7 days.",
+      "footer": "If you didn't expect this invitation, you can safely ignore this email."
+    },
+    "federationInvite": {
+      "subject": "{appName} - Meeting invitation from {fromUser}",
+      "intro": "You have received a meeting invitation from {fromUser}.",
+      "roomLabel": "Room:"
+    },
+    "calendarInvite": {
+      "subject": "{appName} - Calendar invitation from {fromUser}",
+      "intro": "You have received a calendar invitation from {fromUser}."
+    },
+    "calendarDeleted": {
+      "subject": "{appName} - Calendar event cancelled: {title}",
+      "intro": "The following calendar event was deleted by the organiser ({fromUser}) and is no longer available:",
+      "note": "The event has been automatically removed from your calendar.",
+      "footer": "This message was sent automatically by {appName}."
+    }
   }
 }