fix: dedupe scheduling emails, Stalwart-compatible calendar filters

stores/calendar-store.ts

@@ -471,13 +471,9 @@ export const useCalendarStore = create<CalendarStore>()(
           }
 
           set((state) => ({ events: [...state.events, mappedCreated] }));
-          if (sendSchedulingMessages && created.participants) {
-            try {
-              await client.sendImipInvitation(created);
-            } catch (e) {
-              debug.error('Failed to send invitation emails:', e);
-            }
-          }
+          // Invitation emails are sent by the server: `sendSchedulingMessages`
+          // on CalendarEvent/set makes Stalwart queue the iTIP REQUEST itself.
+          // Sending a client-side iMIP copy here produced duplicate emails.
           return mappedCreated;
         } catch (error) {
           debug.error('Failed to create event:', error);
@@ -541,22 +537,9 @@ export const useCalendarStore = create<CalendarStore>()(
               return merged;
             }),
           }));
-          if (sendSchedulingMessages) {
-            const mergedParticipants = cleanUpdates.participants ?? storeEvent?.participants;
-            if (mergedParticipants) {
-              const eventForInvitation = {
-                ...(storeEvent ?? {}),
-                ...cleanUpdates,
-                id: realId,
-                participants: mergedParticipants,
-              } as import('@/lib/jmap/types').CalendarEvent;
-              try {
-                await client.sendImipInvitation(eventForInvitation);
-              } catch (e) {
-                debug.error('Failed to send invitation emails:', e);
-              }
-            }
-          }
+          // Update emails (iTIP REQUEST/REPLY) are sent by the server via the
+          // `sendSchedulingMessages` argument already passed above - a manual
+          // iMIP send here produced duplicate emails.
         } catch (error) {
           debug.error('Failed to update event:', error);
           set({ error: 'Failed to update event' });
@@ -787,16 +770,9 @@ export const useCalendarStore = create<CalendarStore>()(
           const realId = storeEvent?.originalId || stripLocalAccountPrefix(id, storeEvent?.localAccountId);
           const targetAccountId = storeEvent?.accountId;
           client = resolveAccountClient(client, storeEvent?.localAccountId);
-          if (sendSchedulingMessages) {
-            try {
-              const event = await client.getCalendarEvent(realId, targetAccountId);
-              if (event?.participants) {
-                await client.sendImipCancellation(event);
-              }
-            } catch (e) {
-              debug.error('Failed to send cancellation emails:', e);
-            }
-          }
+          // Cancellation emails (iTIP CANCEL) are sent by the server via the
+          // `sendSchedulingMessages` argument on the destroy below - a manual
+          // iMIP send here produced duplicate emails.
           debug.log('calendar', 'Calendar deleteEvent', {
             storeId: id,
             realId,