fix(settings): giữ tên nút chặn mạng cũ và nới cột mục lục

- Trả nhãn công tắc về "Block network for agent-run commands"
  (vi/ja như cũ).
- Cột mục lục bên trái tính độ rộng theo kiểu chữ của mục đang chọn
  (in đậm + lề 10px), trước đây "Sandbox Security Layer" bị cắt.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

presentation/shared/list_sizing.py

@@ -0,0 +1,27 @@
+"""Width of a navigation list whose current row is drawn bold.
+
+The theme draws the selected ``sectionIndex`` row with ``font-weight: 600``
+and 10px padding each side (``theme/qss.py``). Sizing the list from the plain
+font left the selected label too wide for its row, so "Sandbox Security
+Layer" was cut off in Settings as soon as it was picked.
+"""
+from __future__ import annotations
+
+from typing import Iterable
+
+from PySide6.QtGui import QFont, QFontMetrics
+
+#: Item padding (10px x 2) + item radius + list frame, with a little slack.
+ROW_CHROME_PX = 48
+
+
+def selected_label_width(widget, labels: Iterable[str]) -> int:
+    """Pixels needed to show the widest of ``labels`` in the bold selected style."""
+    widget.ensurePolished()
+    bold = QFont(widget.font())
+    bold.setWeight(QFont.Weight.DemiBold)
+    metrics = QFontMetrics(bold)
+    return max((metrics.horizontalAdvance(label) for label in labels), default=0) + ROW_CHROME_PX
+
+
+__all__ = ["ROW_CHROME_PX", "selected_label_width"]