T-Watch target.cpp: fixed preamble = (sf <= 8) ? 32 : 16 to (sf <= 9) which I should have done in the first place to match meshcore PR 1954. Testing on Watch before applying wider change.

T-Watch: So many UI changes. Also swapped render battery indicator to use the AXP2101 gauge for hopefully higher accuracy. Also implemnted meck rx duty cycle for watch builds only to test out power saving effects first on watch build before implementing elsewhere.

src/Dispatcher.cpp

@@ -86,6 +86,7 @@ void Dispatcher::loop() {
       rx_stuck_count = 0;  // radio recovered — reset counter
     }
   }
+#if !defined(MECK_RX_DUTY_CYCLE)
   if (!is_recv && _ms->getMillis() - radio_nonrx_start > 8000) {   // radio has not been in Rx mode for 8 seconds!
     _err_flags |= ERR_EVENT_STARTRX_TIMEOUT;
 
@@ -105,6 +106,7 @@ void Dispatcher::loop() {
     cad_busy_start = 0;
     next_agc_reset_time = futureMillis(getAGCResetInterval());
   }
+#endif
 
   if (outbound) {  // waiting for outbound send to be completed
     if (_radio->isSendComplete()) {
@@ -152,10 +154,12 @@ void Dispatcher::loop() {
     next_agc_reset_time = futureMillis(getAGCResetInterval());
   }
 
+#if !defined(MECK_RX_DUTY_CYCLE)
   if (getAGCResetInterval() > 0 && millisHasNowPassed(next_agc_reset_time)) {
     _radio->resetAGC();
     next_agc_reset_time = futureMillis(getAGCResetInterval());
   }
+#endif
 
   // check inbound (delayed) queue
   {