fix: Improve calendar invite detection and fix DuplicateIds error

- Enhance is_calendar_email() to detect forwarded meeting invites
- Add content-based detection for Teams meetings and ICS data
- Remove fixed ID from CalendarInvitePanel to prevent DuplicateIds
- Fix notify calls in calendar_invite.py (remove call_from_thread)

src/mail/actions/calendar_invite.py

@@ -195,13 +195,12 @@ async def _async_respond_to_invite(
 ):
     """Async worker to find and respond to calendar invite."""
     # First, find the event
-    app.call_from_thread(app.notify, f"Searching for calendar event: {subject[:40]}...")
+    app.notify(f"Searching for calendar event: {subject[:40]}...")
 
     event = await find_event_by_subject(subject, organizer_email)
 
     if not event:
-        app.call_from_thread(
-            app.notify,
+        app.notify(
             f"Could not find calendar event matching: {subject[:40]}",
             severity="warning",
         )
@@ -209,8 +208,7 @@ async def _async_respond_to_invite(
 
     event_id = event.get("id")
     if not event_id:
-        app.call_from_thread(
-            app.notify,
+        app.notify(
             "Could not get event ID from calendar",
             severity="error",
         )
@@ -220,18 +218,14 @@ async def _async_respond_to_invite(
 
     # Check if already responded
     if current_response == "accepted" and response == "accept":
-        app.call_from_thread(
-            app.notify, "Already accepted this invite", severity="information"
-        )
+        app.notify("Already accepted this invite", severity="information")
         return
     elif current_response == "declined" and response == "decline":
-        app.call_from_thread(
-            app.notify, "Already declined this invite", severity="information"
-        )
+        app.notify("Already declined this invite", severity="information")
         return
 
     # Respond to the invite
     success, message = await respond_to_calendar_invite(event_id, response)
 
     severity = "information" if success else "error"
-    app.call_from_thread(app.notify, message, severity=severity)
+    app.notify(message, severity=severity)