do not bootstrap companion rtc

Bootstrapping companion RTC from contact lastmod time meant that if/when
the companion clock strayed into future time because of clock drift,
contacts would get a future/corrupted timestamp -- which the companion
would happily restore upon reboot. And since the firmware rejects
setting time backwards, it could never be fixed even when rebooting,
causing the companion clock to ever drift further ahead.

Resolves #3050

examples/companion_radio/MyMesh.cpp

@@ -957,7 +957,6 @@ void MyMesh::begin(bool has_display) {
 
   resetContacts();
   _store->loadContacts(this);
-  bootstrapRTCfromContacts();
   addChannel("Public", PUBLIC_GROUP_PSK); // pre-configure Andy's public channel
   _store->loadChannels(this);
 

src/helpers/BaseChatMesh.cpp

@@ -55,18 +55,6 @@ void BaseChatMesh::sendAckTo(const ContactInfo& dest, const uint8_t* ack_hash, u
   }
 }
 
-void BaseChatMesh::bootstrapRTCfromContacts() {
-  uint32_t latest = 0;
-  for (int i = 0; i < num_contacts; i++) {
-    if (contacts[i].lastmod > latest) {
-      latest = contacts[i].lastmod;
-    }
-  }
-  if (latest != 0) {
-    getRTCClock()->setCurrentTime(latest + 1);
-  }
-}
-
 ContactInfo* BaseChatMesh::allocateContactSlot(bool transient_only) {
   if (num_contacts < MAX_CONTACTS) {
     return &contacts[num_contacts++];
@@ -166,7 +154,7 @@ void BaseChatMesh::onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id,
       MESH_DEBUG_PRINTLN("onAdvertRecv: unable to allocate contact slot for new contact");
       return;
     }
-    
+
     populateContactFromAdvert(*from, id, parser, timestamp);
     from->sync_since = 0;
     from->shared_secret_valid = false;
@@ -773,7 +761,7 @@ void BaseChatMesh::checkConnections() {
       memcpy(data, &now, 4);
       data[4] = REQ_TYPE_KEEP_ALIVE;
       memcpy(&data[5], &contact->sync_since, 4);
-    
+
       // calc expected ACK reply
       mesh::Utils::sha256((uint8_t *)&connections[i].expected_ack, 4, data, 9, self_id.pub_key, PUB_KEY_SIZE);
 
@@ -781,7 +769,7 @@ void BaseChatMesh::checkConnections() {
       if (pkt) {
         sendDirect(pkt, contact->out_path, contact->out_path_len);
       }
-    
+
       // schedule next KEEP_ALIVE
       connections[i].next_ping = futureMillis(connections[i].keep_alive_millis);
     }

src/helpers/BaseChatMesh.h

@@ -79,7 +79,7 @@ class BaseChatMesh : public mesh::Mesh {
 protected:
   BaseChatMesh(mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::PacketManager& mgr, mesh::MeshTables& tables)
       : mesh::Mesh(radio, ms, rng, rtc, mgr, tables)
-  { 
+  {
     num_contacts = 0;
   #ifdef MAX_GROUP_CHANNELS
     memset(channels, 0, sizeof(channels));
@@ -90,7 +90,6 @@ protected:
     memset(connections, 0, sizeof(connections));
   }
 
-  void bootstrapRTCfromContacts();
   void resetContacts() { num_contacts = 0; }
   void populateContactFromAdvert(ContactInfo& ci, const mesh::Identity& id, const AdvertDataParser& parser, uint32_t timestamp);
   ContactInfo* allocateContactSlot(bool transient_only=false); // helper to find slot for new contact