Add persistent notifications for priority 10 messages

- Implement custom PersistentNotification widget with flashing background
- Add settings for persistent priority 10 notifications and sound control
- Modify notification logic to show persistent pop-ups for priority 10
- Allow closing all persistent notifications via tray icon click
- Add AGENTS.md with type checking guidelines
- Configure pyright to suppress PyQt6 false positives
- Update UI in settings dialog for new options
- Add notification sound file

gotify_tray/gui/widgets/PersistentNotification.py

@@ -0,0 +1,145 @@
+import logging
+
+from PyQt6 import QtCore, QtGui, QtWidgets
+
+logger = logging.getLogger("gotify-tray")
+
+
+class PersistentNotification(QtWidgets.QWidget):
+    close_all_requested = QtCore.pyqtSignal()
+
+    def __init__(
+        self,
+        title: str,
+        message: str,
+        icon: QtGui.QIcon | QtWidgets.QSystemTrayIcon.MessageIcon,
+        y_offset: int = 0,
+        flash: bool = False,
+        parent=None,
+    ):
+        super().__init__(parent)
+        self.y_offset = y_offset
+        self.flash = flash
+        self.flash_state = False
+        self.original_stylesheet = ""
+        self.setWindowFlags(
+            QtCore.Qt.WindowType.Window
+            | QtCore.Qt.WindowType.FramelessWindowHint
+            | QtCore.Qt.WindowType.WindowStaysOnTopHint
+        )
+        self.setAttribute(QtCore.Qt.WidgetAttribute.WA_OpaquePaintEvent, True)
+        self.setAttribute(QtCore.Qt.WidgetAttribute.WA_ShowWithoutActivating)
+
+        # Layout
+        layout = QtWidgets.QHBoxLayout(self)
+        layout.setContentsMargins(10, 10, 10, 10)
+        layout.setSpacing(10)
+
+        # Icon
+        self.icon_label = QtWidgets.QLabel()
+        if isinstance(icon, QtGui.QIcon):
+            self.icon_label.setPixmap(icon.pixmap(32, 32))
+        else:
+            # For MessageIcon
+            if icon == QtWidgets.QSystemTrayIcon.MessageIcon.Information:
+                standard_icon = QtWidgets.QStyle.StandardPixmap.SP_MessageBoxInformation
+            elif icon == QtWidgets.QSystemTrayIcon.MessageIcon.Warning:
+                standard_icon = QtWidgets.QStyle.StandardPixmap.SP_MessageBoxWarning
+            elif icon == QtWidgets.QSystemTrayIcon.MessageIcon.Critical:
+                standard_icon = QtWidgets.QStyle.StandardPixmap.SP_MessageBoxCritical
+            else:
+                standard_icon = QtWidgets.QStyle.StandardPixmap.SP_MessageBoxInformation
+            system_icon = self.style().standardIcon(standard_icon)
+            self.icon_label.setPixmap(system_icon.pixmap(32, 32))
+        layout.addWidget(self.icon_label)
+
+        # Text
+        text_layout = QtWidgets.QVBoxLayout()
+        self.title_label = QtWidgets.QLabel(title)
+        self.title_label.setStyleSheet("font-weight: bold;")
+        text_layout.addWidget(self.title_label)
+
+        self.message_label = QtWidgets.QLabel(message)
+        self.message_label.setWordWrap(True)
+        text_layout.addWidget(self.message_label)
+
+        layout.addLayout(text_layout, 1)
+
+        # Close button
+        self.close_button = QtWidgets.QPushButton("×")
+        self.close_button.setFixedSize(20, 20)
+        self.close_button.clicked.connect(self._on_close)
+        layout.addWidget(self.close_button)
+
+        # Style
+        self.setAutoFillBackground(True)
+        self.setBackgroundRole(QtGui.QPalette.ColorRole.Window)
+        palette = self.palette()
+        palette.setColor(QtGui.QPalette.ColorRole.Window, QtGui.QColor("white"))
+        palette.setColor(QtGui.QPalette.ColorRole.WindowText, QtGui.QColor("red"))
+        self.setPalette(palette)
+
+        self.setStyleSheet("""
+            PersistentNotification {
+                border-radius: 10px;
+                border: 1px solid rgba(100, 100, 100, 200);
+            }
+            QPushButton {
+                background-color: transparent;
+                color: white;
+                border: none;
+                font-size: 16px;
+            }
+            QPushButton:hover {
+                background-color: rgba(100, 100, 100, 100);
+            }
+        """)
+
+        if self.flash:
+            self.flash_timer = QtCore.QTimer(self)
+            self.flash_timer.timeout.connect(self._toggle_flash)
+
+        # Size and position
+        self.adjustSize()
+        self.setFixedWidth(300)
+        self._position()
+
+        # Timer for fade out if not clicked, but since persistent, maybe not needed
+        # But to avoid staying forever if forgotten, perhaps auto-close after long time
+        # But user wants until clicked, so no timer.
+
+    def _position(self):
+        screen = QtWidgets.QApplication.primaryScreen().availableGeometry()
+        # Stack from bottom right
+        self.move(
+            screen.width() - self.width() - 10,
+            screen.height() - self.height() - 50 - self.y_offset,
+        )
+
+    def _toggle_flash(self):
+        self.flash_state = not self.flash_state
+        palette = self.palette()
+        if self.flash_state:
+            palette.setColor(QtGui.QPalette.ColorRole.Window, QtGui.QColor("red"))
+            palette.setColor(QtGui.QPalette.ColorRole.WindowText, QtGui.QColor("white"))
+        else:
+            palette.setColor(QtGui.QPalette.ColorRole.Window, QtGui.QColor("white"))
+            palette.setColor(QtGui.QPalette.ColorRole.WindowText, QtGui.QColor("red"))
+        self.setPalette(palette)
+        self.update()
+        self.repaint()
+
+    def mousePressEvent(self, event):
+        self._on_close()
+
+    def _on_close(self):
+        if self.flash:
+            self.flash_timer.stop()
+        self.close_all_requested.emit()
+        self.close()
+
+    def showEvent(self, event):
+        super().showEvent(event)
+        self.raise_()
+        if self.flash:
+            self.flash_timer.start(1000)