feat: add letters feature with detail view and listingHEADmain

- Introduced new routes for letters and their details.
- Created pages for displaying letter details and listing letters.
- Added new types for letters, including participants, messages, and attachments.
- Implemented API calls for fetching letters and managing messages (reply, edit, delete).
- Enhanced stats to include unread letters and pending districts for staff users.
- Updated styles for letters and their components.
- Added privacy settings for letters (public and friends).
- Modified user model to include letter privacy settings.
- Improved error handling and user feedback in the UI.

1 files changed, 3 insertions, 0 deletions

diff --git a/shrine/services/letter.go b/shrine/services/letter.go
index 20a4f93..c7ea741 100644
--- a/shrine/services/letter.go
+++ b/shrine/services/letter.go
@@ -75,6 +75,9 @@ func CreateLetter(userID uint, request letter.CreateRequest) (*common.MessageRes
 		if recipient.ID == userID {
 			continue
 		}
+		if recipient.LetterPrivacy == enums.LetterPrivacyFriends {
+			return nil, fail(enums.BadRequest, fmt.Sprintf(messages.RecipientNotAcceptingLetters, username))
+		}
 		recipientIDs = append(recipientIDs, recipient.ID)
 	}