fix: remove duplicate atlas toggle button markup (#1442)

tests/test_hud_toggle_buttons.py

@@ -0,0 +1,21 @@
+from pathlib import Path
+
+
+def _hud_button_block() -> str:
+    text = (Path(__file__).resolve().parents[1] / 'index.html').read_text(encoding='utf-8')
+    start = text.index('<!-- Top Right: Agent Log, Atlas & SOUL Toggle -->')
+    end = text.index('<div id="bannerlord-status"')
+    return text[start:end]
+
+
+def test_hud_toggle_buttons_have_unique_ids():
+    block = _hud_button_block()
+    assert block.count('id="atlas-toggle-btn"') == 1
+    assert block.count('id="soul-toggle-btn"') == 1
+    assert block.count('id="mode-toggle-btn"') == 1
+
+
+def test_hud_toggle_buttons_are_balanced_and_closed():
+    block = _hud_button_block()
+    assert block.count('<button') == 3
+    assert block.count('</button>') == 3