feat(api,userbot,frontend): search peers without chats and start tracking them

backend/src/utils/read/models.py

@@ -38,6 +38,19 @@ class ChatListItem(BaseModel):
     last_sender_id: int | None
 
 
+class DiscoverItem(BaseModel):
+    chat_id: int
+    title: str | None
+    username: str | None
+    kind: str
+    is_bot: bool
+    is_contact: bool
+    has_avatar: bool
+    message_count: int
+    in_dialogs: bool
+    tracked: bool
+
+
 class EntityView(BaseModel):
     type: str
     offset: int