contacts: granular autoadd and overwrite-oldest

src/helpers/BaseChatMesh.h

@@ -89,9 +89,14 @@ protected:
   }
 
   void resetContacts() { num_contacts = 0; }
+  ContactInfo* allocateContactSlot(); // helper to find slot for new contact
 
   // 'UI' concepts, for sub-classes to implement
   virtual bool isAutoAddEnabled() const { return true; }
+  virtual bool shouldAutoAddContactType(uint8_t type) const { return true; }
+  virtual void onContactsFull() {};
+  virtual bool shouldOverwriteWhenFull() const { return false; }
+  virtual void onContactOverwrite(const uint8_t* pub_key) {};
   virtual void onDiscoveredContact(ContactInfo& contact, bool is_new, uint8_t path_len, const uint8_t* path) = 0;
   virtual ContactInfo* processAck(const uint8_t *data) = 0;
   virtual void onContactPathUpdated(const ContactInfo& contact) = 0;