Implement greet inbox and outbox

- Add user_greet model and startup table sync
- Implement /greet/user and /greet/delete handlers
- Implement noticeFriendGreeting inbox and noticeUserGreetingHistory outbox
- Return peer profile and center unit info for greeting notices
- Update login topInfo friend greet counters from unread inbox messages

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/handler.go

@@ -11,6 +11,7 @@ import (
 	_ "honoka-chan/internal/handler/friend"
 	_ "honoka-chan/internal/handler/gdpr"
 	_ "honoka-chan/internal/handler/ghome"
+	_ "honoka-chan/internal/handler/greet"
 	_ "honoka-chan/internal/handler/lbonus"
 	_ "honoka-chan/internal/handler/live"
 	_ "honoka-chan/internal/handler/login"