feat: tray-first UX, text outline, start-at-login toggle, font max 200

- All settings move to flat tray menu; right-click on clock disabled
- ClockLabel: custom QPainterPath text rendering with configurable
  glyph outline (BorderColor) — verified pixel-level offscreen
- Fixed glyph positioning bug (baseline math) caught by isolated test
- Window auto-fits content (adjustSize) — no more oversized clock
- Start at Login: checkable tray item, persisted in QSettings,
  LaunchAgent enable/disable (TDD: roundTrip test caught disable()
  returning false when plist already absent)
- Color dialog: hex/HTML input + 'transparent' + native picker fallback;
  opaque colors stored as #RRGGBB
- Border: glyph outline instead of box border; background still painted
  in paintEvent (QSS doesn't render with WA_TranslucentBackground on macOS)
- Removed window shadow (setHasShadow:NO), no bold, SF Pro Rounded
- Font size dialogs allow up to 200 (was 72)
- macOS: icon template 16pt, light/dark auto-adapt; LaunchAgent points
  to /Applications install

autostart_manager.cpp

@@ -14,6 +14,15 @@ const QString launchAgentLabel = QStringLiteral("com.clouck.clock");
 
 bool AutoStartManager::enableForCurrentApplication()
 {
+#ifdef Q_OS_MAC
+    return enableForPath(QCoreApplication::applicationFilePath());
+#else
+    return false;
+#endif
+}
+
+bool AutoStartManager::enableForPath(const QString &executablePath)
+{
 #ifdef Q_OS_MAC
     const QString agentPath = launchAgentPath();
     if (agentPath.isEmpty())
@@ -33,8 +42,32 @@ bool AutoStartManager::enableForCurrentApplication()
         return false;
     }
 
-    agentFile.write(launchAgentContents(QCoreApplication::applicationFilePath()).toUtf8());
+    agentFile.write(launchAgentContents(executablePath).toUtf8());
     return agentFile.commit();
+#else
+    Q_UNUSED(executablePath);
+    return false;
+#endif
+}
+
+bool AutoStartManager::disable()
+{
+#ifdef Q_OS_MAC
+    const QString agentPath = launchAgentPath();
+    if (agentPath.isEmpty() || !QFile::exists(agentPath))
+    {
+        return true; // already gone — desired state reached
+    }
+    return QFile::remove(agentPath);
+#else
+    return false;
+#endif
+}
+
+bool AutoStartManager::isEnabled()
+{
+#ifdef Q_OS_MAC
+    return QFile::exists(launchAgentPath());
 #else
     return false;
 #endif