fix(ui): light-mode polish — nav hover, graph theme tokens, title alignment

src/pygui/backend/visualization/graph_quick_item.py

@@ -117,7 +117,7 @@ class GraphQuickItem(QQuickPaintedItem):
 
         self._min_y: float = 0.0
         self._max_y: float = 150.0
-        self._padding: dict[str, int] = {"left": 60, "right": 20, "top": 30, "bottom": 50}
+        self._padding: dict[str, int] = {"left": 60, "right": 20, "top": 44, "bottom": 50}
 
         # Viewport (replay chart zoom/pan): defaults reproduce "whole series",
         # so the Graph tab (which never sets these) is unaffected. See
@@ -462,8 +462,8 @@ class GraphQuickItem(QQuickPaintedItem):
             painter.setFont(title_font)
             painter.setPen(QPen(self._text_color))
             painter.drawText(
-                QRectF(0, 4, w, 24),
-                Qt.AlignmentFlag.AlignHCenter,
+                QRectF(8, 4, w - 8, 24),
+                Qt.AlignmentFlag.AlignLeft | Qt.AlignmentFlag.AlignVCenter,
                 self._title,
             )
 
@@ -649,5 +649,5 @@ class GraphQuickItem(QQuickPaintedItem):
         painter.drawText(
             pr,
             Qt.AlignmentFlag.AlignCenter,
-            "No data — read a wafer or open a CSV file",
+            "No data — select a CSV file to view the graph",
         )

src/pygui/backend/visualization/wafer_map_item.py

@@ -124,7 +124,7 @@ class WaferMapItem(QQuickPaintedItem):
         self._margin:   float = 1.0
         self._blend:    float = 0.0
         self._show_labels: bool = True
-        self._show_extremes: bool = True
+        self._show_extremes: bool = False
         self._shape: str = "round"
         self._size: float = 300.0
         self._thickness_data: list[list[float]] = []  # [x_mm, y_mm, t2] triples