feat(settings/espnow): validate wifi_channel and wire into firmware

src/controllers/settings.py

@@ -55,15 +55,28 @@ async def configure_ap(request):
     except Exception as e:
         return json.dumps({"error": str(e)}), 500
 
+def _validate_wifi_channel(value):
+    """Return int 1–11 or raise ValueError."""
+    ch = int(value)
+    if ch < 1 or ch > 11:
+        raise ValueError("wifi_channel must be between 1 and 11")
+    return ch
+
+
 @controller.put('/settings')
 async def update_settings(request):
     """Update general settings."""
     try:
         data = request.json
         for key, value in data.items():
-            settings[key] = value
+            if key == 'wifi_channel' and value is not None:
+                settings[key] = _validate_wifi_channel(value)
+            else:
+                settings[key] = value
         settings.save()
         return json.dumps({"message": "Settings updated successfully"}), 200, {'Content-Type': 'application/json'}
+    except ValueError as e:
+        return json.dumps({"error": str(e)}), 400
     except Exception as e:
         return json.dumps({"error": str(e)}), 500
 

src/settings.py

@@ -45,6 +45,9 @@ class Settings(dict):
             self['session_secret_key'] = self.generate_secret_key()
             # Save immediately when generating a new key
             self.save()
+        # ESP-NOW STA channel (2.4 GHz) for LED drivers / bridge alignment; 1–11
+        if 'wifi_channel' not in self:
+            self['wifi_channel'] = 6
 
     def save(self):
         try: