refactor(src/services): improve property caching and simplify DBus property handling

Add internal property cache to reduce DBus round‑trips and streamline signal handling.
It also adjusts proxy flags and error handling for better robustness.

src/services/battery.py

@@ -95,13 +95,14 @@ class Battery(Service):
         self._bus: Gio.DBusConnection | None = None
         self._proxy = None
         self._power_profile_proxy = None
+        self._prop_cache: dict[str, any] = {}
         self.do_register()
 
     def do_register(self) -> None:
         self._bus = Gio.bus_get_sync(Gio.BusType.SYSTEM)
         self._proxy = Gio.DBusProxy.new_sync(
             self._bus,
-            Gio.DBusProxyFlags.USE_PROPERTY_CHANGED,
+            Gio.DBusProxyFlags.NONE,
             None,
             BATTERY_BUS_NAME,
             BATTERY_BUS_PATH,
@@ -124,7 +125,7 @@ class Battery(Service):
         try:
             self._power_profile_proxy = Gio.DBusProxy.new_sync(
                 self._bus,
-                Gio.DBusProxyFlags.USE_PROPERTY_CHANGED,
+                Gio.DBusProxyFlags.NONE,
                 None,
                 POWER_PROFILE_BUS_NAME,
                 POWER_PROFILE_BUS_PATH,
@@ -144,7 +145,21 @@ class Battery(Service):
         except Exception as e:
             logger.warning(f"[Battery] Power Profiles daemon not available: {e}")
 
-    def do_handle_property_change(self, *_):
+    def do_handle_property_change(
+        self,
+        _connection: Gio.DBusConnection,
+        _sender_name: str,
+        _object_path: str,
+        _interface_name: str,
+        _signal_name: str,
+        parameters: GLib.Variant,
+    ):
+        try:
+            _iface, changed_props, _invalidated = parameters.unpack()
+            for prop_name, variant in changed_props.items():
+                self._prop_cache[prop_name] = variant.unpack()
+        except Exception as e:
+            logger.warning(f"[Battery] Failed to parse PropertiesChanged: {e}")
         self.emit("changed")
 
     def do_handle_power_profile_change(self, *_):
@@ -175,8 +190,13 @@ class Battery(Service):
         return result.unpack()
 
     def do_get_cached_property(self, property_name):
+        if property_name in self._prop_cache:
+            return self._prop_cache[property_name]
         result = self._proxy.get_cached_property(property_name)
-        return result.unpack() if result is not None else None
+        value = result.unpack() if result is not None else None
+        if value is not None:
+            self._prop_cache[property_name] = value
+        return value
 
     def get_power_profile(self) -> str | None:
         """Get the current active power profile."""