fix(webpage): hide Temperatures section when setup has no temperature data

renderInstrument() checked setup.temperatures for truthiness, but an
empty JS object is truthy, so LamNI's deliberately-empty temperatures
dict (it has no monitoring device) still rendered an empty
"Temperatures" heading/table. flomni only worked by coincidence since
its _TEMP_MAP always has entries. Adds a hasTemps check
(Object.keys(...).length>0), mirroring the existing hasParams idiom
one line above for the same card.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

csaxs_bec/bec_ipython_client/plugins/OMNY_shared/webpage_generator_base.py

@@ -2610,7 +2610,8 @@ function renderInstrument(setup){{
   const card=document.getElementById('instrument-card'),grid=document.getElementById('instrument-grid');
   const cp=(setup&&setup.current_params)||null;
   const hasParams=cp&&Object.keys(cp).length>0;
-  if(!setup||(!setup.temperatures&&!hasParams)){{card.style.display='none';return;}}
+  const hasTemps=setup&&setup.temperatures&&Object.keys(setup.temperatures).length>0;
+  if(!setup||(!hasTemps&&!hasParams)){{card.style.display='none';return;}}
   card.style.display='';
   let html='';
   if(hasParams){{
@@ -2622,7 +2623,7 @@ function renderInstrument(setup){{
     html+=buildParamRows(cp);
     html+='</table></div>';
   }}
-  if(setup.temperatures){{
+  if(hasTemps){{
     html+='<div class="instrument-section"><h3>Temperatures (&deg;C)</h3><table class="kv-table">';
     for(const[k,v] of Object.entries(setup.temperatures)){{
       const cls=v==null?' class="temp-null"':'';