Add optional Home Assistant integration for battery percentage tracking

templates/battery_detail.html

@@ -67,6 +67,18 @@
     {{ meta_row("Charge Cycles", battery.charge_cycles) }}
     {{ meta_row("Purchase Date", battery.purchase_date) }}
     {{ meta_row("Storage", battery.storage_location) }}
+    {% if battery.battery_percentage is not none %}
+    <tr>
+      <td style="padding:0.3rem 1rem 0.3rem 0;font-weight:600;color:#64748b;border:none;">Battery %</td>
+      <td style="border:none;">
+        {% if battery.battery_percentage < 20 %}
+          <span class="badge badge-warning">⚠ {{ battery.battery_percentage }}% — consider replacing</span>
+        {% else %}
+          {{ battery.battery_percentage }}%
+        {% endif %}
+      </td>
+    </tr>
+    {% endif %}
     {% if battery.notes %}
     <tr>
       <td style="padding:0.3rem 1rem 0.3rem 0;font-weight:600;color:#64748b;border:none;">Notes</td>
@@ -261,6 +273,13 @@
                value="{{ battery.purchase_date or '' }}">
       </div>
 
+      <div class="form-group">
+        <label for="battery_percentage">Battery % (optional)</label>
+        <input type="number" id="battery_percentage" name="battery_percentage" min="0" max="100"
+               value="{{ battery.battery_percentage if battery.battery_percentage is not none else '' }}"
+               placeholder="e.g. 85">
+      </div>
+
     </div>
 
     <div class="form-group">