Restore indoor sensor display and restructure dashboard layout

- Restore tempinf/humidityin tiles from PWS data on index.html (removed
  with thermostat cleanup but still available from Ambient station)
- Dashboard: replace two flat secondary-stat grids with labeled section
  cards — Wind, Precipitation, Climate, Indoor — for clearer visual
  hierarchy and category separation
- Indoor section card includes Ecobee portal link; appears only when
  station reports indoor sensor data

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/public/index.html

@@ -289,6 +289,11 @@
                 <div class="stat-label">Solar Rad.</div>
                 <div class="stat-val"><span id="st-solar">--</span> <span class="stat-unit">W/m²</span></div>
               </div>
+              <div class="stat-card hidden" id="st-indoor-card">
+                <div class="stat-label">Indoor Temp</div>
+                <div class="stat-val"><span id="st-tempin">--</span>°<span id="st-tempin-unit">F</span></div>
+                <div class="stat-sub" id="st-humin"></div>
+              </div>
             </div>
           </div>
           <div id="station-error" class="station-error hidden"></div>