refactor: remove redundant Box wrappers

- dock/main.py: canvas_box eliminated, Revealer wraps canvas directly
- desktop/system.py: two single-child Box wrappers removed
- controlcenter/player.py: redundant album_cover wrapper removed
- controlcenter/expanded_player.py: same pattern as player.py

src/window/controlcenter/expanded_player.py

@@ -94,7 +94,9 @@ class PlayerBoxStack(Box):
 
     def _create_no_media_box(self):
         fallback_cover_path = PLAYER_FALLBACK_ART
-        album_cover = Box(style_classes="album-image-c")
+        album_cover = Box(
+            style_classes="album-image-c", h_align="start", v_align="center"
+        )
         album_cover.set_style(f"background-image:url('{fallback_cover_path}')")
 
         track_title = Label(
@@ -131,12 +133,7 @@ class PlayerBoxStack(Box):
                             h_expand=True,
                             children=[track_info],
                         ),
-                        Box(
-                            h_align="start",
-                            v_align="center",
-                            name="player-image-stack",
-                            children=[album_cover],
-                        ),
+                        album_cover,
                     ],
                 )
             ],
@@ -291,19 +288,18 @@ class PlayerBox(Box):
         self._seekbar_signal_ids = []
         self._cached_duration = 0
 
-        self.album_cover = Box(style_classes="album-image-c")
+        self.album_cover = Box(
+            style_classes="album-image-c",
+            h_align="start",
+            v_align="center",
+        )
         self.album_cover.set_style(
             f"background-image:url('{self.fallback_cover_path}')"
         )
         self.album_cover.set_size_request(70, 70)
 
         self.image = Overlay(
-            child=Box(
-                h_align="start",
-                v_align="center",
-                name="player-image-stack",
-                children=[self.album_cover],
-            ),
+            child=self.album_cover,
             overlays=[
                 Box(
                     children=Image(

src/window/controlcenter/player.py

@@ -144,7 +144,7 @@ class PlayerBoxStack(Box):
 
         inner_box = CenterBox(
             name="inner-player-box",
-            start_children=[Box(style_classes="album-image-c", children=album_cover)],
+            start_children=[album_cover],
             center_children=[
                 Box(
                     name="player-info-box-c",
@@ -317,16 +317,13 @@ class PlayerBox(Box):
         self.exit = False
         self._signal_connections = []
 
-        self.album_cover = Box(style_classes="album-image-c")
+        self.album_cover = Box(
+            style_classes="album-image-c", h_align="start", v_align="center"
+        )
         self.album_cover.set_style(f"background-image:url('{self.cover_path}')")
 
         self.image = Overlay(
-            child=Box(
-                h_align="start",
-                v_align="center",
-                name="player-image-stack",
-                children=[self.album_cover],
-            ),
+            child=self.album_cover,
             overlays=[
                 Box(
                     children=Image(

src/window/desktop/system.py

@@ -53,22 +53,13 @@ class SystemInfoBase(Box):
                 spacing=12,
                 h_align="center",
                 v_align="center",
-                children=[
-                    Box(
                 children=[
                     Overlay(
                         child=self.progress,
                         tooltip_text="",
                         overlays=self.main_label,
-                            )
-                        ]
-                    ),
-                    Box(
-                        h_align="center",
-                        justification="centre",
-                        orientation="v",
-                        children=[self.info_container],
                     ),
+                    self.info_container,
                 ],
             )
         )

src/window/dock/main.py

@@ -28,14 +28,10 @@ class Dock(Window):
         self.set_app_paintable(True)
 
         self.canvas = DockCanvas(self)
-
-        canvas_box = Box(
-            name="dock-canvas-box",
-            children=[self.canvas],
-        )
+        self.canvas.set_name("dock-canvas-box")
 
         self.revealer = Revealer(
-            child=canvas_box,
+            child=self.canvas,
             transition_duration=200,
             transition_type="slide-up",
         )