fix: hover invisible when theme.hover == background, remove CSS on QMenuBar

Move hover color fixup into Theme::fromJson so all consumers get a
visible hover automatically. Remove duplicate lighter(130) fallback
from applyGlobalTheme. Replace QMenuBar CSS with QPalette so
MenuBarStyle QProxyStyle is not bypassed. Add PE_PanelMenuBar and
CE_MenuBarEmptyArea suppression so Fusion never paints over the
title bar background.

tools/test_hover.py

@@ -0,0 +1,159 @@
+"""
+Structural hover test: validate that all themes produce visible hover colors
+and that the QProxyStyle code handles the required control elements.
+
+No pixel sampling — checks theme JSON values and source code patterns.
+"""
+import json
+import os
+import re
+import sys
+
+
+def hex_to_rgb(h):
+    h = h.lstrip('#')
+    return tuple(int(h[i:i+2], 16) for i in (0, 2, 4))
+
+
+def color_dist(c1, c2):
+    return sum(abs(a - b) for a, b in zip(c1, c2))
+
+
+def lighter_130(rgb):
+    """Approximate Qt's QColor::lighter(130) for dark grays."""
+    r, g, b = rgb
+    return (min(255, int(r * 1.3) + 1),
+            min(255, int(g * 1.3) + 1),
+            min(255, int(b * 1.3) + 1))
+
+
+def load_themes():
+    themes = {}
+    theme_dir = os.path.join(os.path.dirname(__file__),
+                             '..', 'src', 'themes', 'defaults')
+    if not os.path.isdir(theme_dir):
+        return themes
+    for name in os.listdir(theme_dir):
+        if name.endswith('.json'):
+            with open(os.path.join(theme_dir, name)) as f:
+                themes[name] = json.load(f)
+    return themes
+
+
+def test_hover_visibility(themes):
+    """Every theme must have hover visually distinct from background.
+    If raw values are identical, Theme::fromJson applies lighter(130)."""
+    ok = True
+    for name, data in sorted(themes.items()):
+        bg = hex_to_rgb(data['background'])
+        hover = hex_to_rgb(data['hover'])
+        dist = color_dist(bg, hover)
+
+        if dist < 20:
+            # fromJson will fix this — verify the fix produces sufficient contrast
+            fixed = lighter_130(bg)
+            fixed_dist = color_dist(bg, fixed)
+            if fixed_dist < 15:
+                print(f"  FAIL: {name}: hover==bg and lighter(130) still too close "
+                      f"(dist={fixed_dist})")
+                ok = False
+            else:
+                print(f"  OK:   {name}: hover==bg, fromJson fixup -> "
+                      f"dist {dist}->{fixed_dist}")
+        else:
+            print(f"  OK:   {name}: hover distinct (dist={dist})")
+    return ok
+
+
+def test_proxystyle_handlers():
+    """Verify MenuBarStyle handles CE_MenuBarItem, CE_MenuItem, CE_MenuBarEmptyArea."""
+    src = os.path.join(os.path.dirname(__file__), '..', 'src', 'main.cpp')
+    with open(src) as f:
+        code = f.read()
+
+    required = {
+        'CE_MenuBarItem':      r'element\s*==\s*CE_MenuBarItem',
+        'CE_MenuItem':         r'element\s*==\s*CE_MenuItem',
+        'CE_MenuBarEmptyArea': r'element\s*==\s*CE_MenuBarEmptyArea',
+        'State_Selected':      r'State_Selected',
+        'QPalette::Mid':       r'QPalette::Mid',
+    }
+
+    ok = True
+    for label, pattern in required.items():
+        if re.search(pattern, code):
+            print(f"  OK:   MenuBarStyle handles {label}")
+        else:
+            print(f"  FAIL: MenuBarStyle missing {label}")
+            ok = False
+    return ok
+
+
+def test_no_menubar_css():
+    """Verify no CSS stylesheet is set on QMenuBar (would bypass QProxyStyle)."""
+    src_dir = os.path.join(os.path.dirname(__file__), '..', 'src')
+    ok = True
+    for root, _, files in os.walk(src_dir):
+        for fname in files:
+            if not fname.endswith('.cpp'):
+                continue
+            path = os.path.join(root, fname)
+            with open(path, encoding='utf-8', errors='replace') as f:
+                for i, line in enumerate(f, 1):
+                    # Check for menuBar/m_menuBar stylesheet calls
+                    if ('menuBar' in line or 'm_menuBar' in line) and \
+                       'setStyleSheet' in line:
+                        print(f"  FAIL: CSS on QMenuBar at {fname}:{i}: "
+                              f"{line.strip()}")
+                        ok = False
+    if ok:
+        print("  OK:   No CSS on QMenuBar")
+    return ok
+
+
+def test_hover_fixup_in_fromjson():
+    """Verify Theme::fromJson applies the hover fixup."""
+    src = os.path.join(os.path.dirname(__file__),
+                       '..', 'src', 'themes', 'theme.cpp')
+    with open(src) as f:
+        code = f.read()
+
+    if 'lighter(130)' in code and 't.hover' in code:
+        print("  OK:   Theme::fromJson has hover fixup")
+        return True
+    else:
+        print("  FAIL: Theme::fromJson missing hover fixup")
+        return False
+
+
+def main():
+    themes = load_themes()
+    if not themes:
+        print("FAIL: No theme files found")
+        return 1
+
+    all_ok = True
+
+    print("--- Test 1: Hover visibility across themes ---")
+    all_ok &= test_hover_visibility(themes)
+
+    print("\n--- Test 2: QProxyStyle handles required elements ---")
+    all_ok &= test_proxystyle_handlers()
+
+    print("\n--- Test 3: No CSS on QMenuBar ---")
+    all_ok &= test_no_menubar_css()
+
+    print("\n--- Test 4: Theme::fromJson hover fixup ---")
+    all_ok &= test_hover_fixup_in_fromjson()
+
+    print(f"\n{'='*50}")
+    if all_ok:
+        print("ALL HOVER TESTS PASSED")
+        return 0
+    else:
+        print("SOME HOVER TESTS FAILED")
+        return 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())