Add Battery Sensor functionality and integrate with display and app

- Implement BatterySensor class to monitor battery voltage and status.
- Update App to initialize and loop BatterySensor.
- Modify FaceRenderer to display battery status on the screen.
- Enhance Display class with a method to draw battery icon.
- Update WebUI to include battery status in the interface.
- Refactor WiFiManager to improve connection handling and logging.
- Adjust Settings to include factory reset functionality.
- Improve HTML structure and styling in WebUI for better user experience.

src/ui/FaceRenderer.h

@@ -3,13 +3,14 @@
 #include "../ui/Display.h"
 #include "../settings/Settings.h"
 #include "../sensors/MoistureSensor.h"
+#include "../sensors/BatterySensor.h"
 
 class FaceRenderer {
 public:
   enum Mood { HAPPY, DRY, TOO_WET };
 
   void begin(Display& display, Settings& settings);
-  void loop(const MoistureSensor& moisture);
+  void loop(const MoistureSensor& moisture, const BatterySensor& battery);
 
   bool isDeadMode() const { return _deadMode; }
   Mood mood() const { return _mood; }
@@ -55,8 +56,8 @@ private:
   void updateDry(unsigned long now);
   void updateTooWet(unsigned long now);
 
-  void renderDead(unsigned long now);
-  void renderNormal(unsigned long now);
+  void renderDead(unsigned long now, const BatterySensor& battery);
+  void renderNormal(unsigned long now, const BatterySensor& battery);
 
   void drawEyesOpen(int pupilDx, int pupilDy);
   void drawEyesClosed();