Add .labui file association — open by double-click, cross-platform

Windows/Linux self-register via core/file_association.py (winreg /
XDG .desktop+mime), triggered from a new Settings button since there's
no installer to do it at install time. macOS gets it at build time via
labui.spec's new BUNDLE() step (CFBundleDocumentTypes in Info.plist) —
that step also makes mac builds a real .app bundle for the first time,
not just a bare onedir folder. main.py gains a LabUIApplication
subclass to catch the macOS QFileOpenEvent (buffered if it arrives
before MainWindow exists) plus argv[1] handling for Windows/Linux.
ProfileButton.load_path() extracted so both paths share the same
load-and-apply logic as the existing file-dialog flow.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 31 insertions, 2 deletions

diff --git a/main.py b/main.py
index 26fcaaf..414d06f 100644
--- a/main.py
+++ b/main.py
@@ -12,10 +12,31 @@ import sys, os
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
 
 from PyQt6.QtWidgets import QApplication
-from PyQt6.QtCore import qInstallMessageHandler, QtMsgType
+from PyQt6.QtCore import qInstallMessageHandler, QtMsgType, QEvent
 from ui.main_window import MainWindow
 
 
+class LabUIApplication(QApplication):
+    """Catches the macOS "open with" launch event (QFileOpenEvent) for a
+    double-clicked .labui file — delivered via this event, not argv, and
+    can arrive before or after MainWindow exists, so it's buffered."""
+
+    def __init__(self, argv):
+        super().__init__(argv)
+        self.file_to_open: str | None = None
+        self.main_window = None
+
+    def event(self, e):
+        if e.type() == QEvent.Type.FileOpen:
+            path = e.file()
+            if self.main_window is not None:
+                self.main_window.load_profile_path(path)
+            else:
+                self.file_to_open = path
+            return True
+        return super().event(e)
+
+
 def _qt_message_handler(msg_type, context, message):
     """Silence one specific, harmless Qt warning: the native windowsvista
     style's combo-box/menu popup code calls QFont::setPointSize() on a
@@ -36,7 +57,7 @@ def _qt_message_handler(msg_type, context, message):
 
 def main():
     qInstallMessageHandler(_qt_message_handler)
-    app = QApplication(sys.argv)
+    app = LabUIApplication(sys.argv)
     app.setApplicationName("LabUI")
 
     qss = os.path.join(os.path.dirname(os.path.abspath(__file__)), "ui", "style_dark.qss")
@@ -45,7 +66,15 @@ def main():
             app.setStyleSheet(f.read())
 
     win = MainWindow()
+    app.main_window = win
     win.show()
+
+    # Opened via double-click / CLI argv (Windows, Linux) or the buffered
+    # macOS FileOpen event (see LabUIApplication.event above).
+    path = app.file_to_open or (sys.argv[1] if len(sys.argv) > 1 else None)
+    if path and path.lower().endswith(".labui") and os.path.isfile(path):
+        win.load_profile_path(path)
+
     sys.exit(app.exec())