feat: add recurring event deletion with three modes

Implement three deletion modes for recurring events:
- single: exclude specific occurrence via EXDATE mechanism
- future: set RRULE UNTIL to stop future occurrences
- all: delete entire event series

Changes include:
- Add exceptionDates field to CalendarEvent model
- Add RecurringDeleteMode type and DeleteRecurringEventDTO
- EventService.deleteRecurring() with mode-based logic using rrule library
- EventController DELETE endpoint accepts mode/occurrenceDate query params
- recurrenceExpander filters out exception dates during expansion
- AI tools support deleteMode and occurrenceDate for proposed deletions
- ChatService.confirmEvent() handles recurring delete modes
- New DeleteEventModal component for unified delete confirmation UI
- Calendar screen integrates modal for both recurring and non-recurring events

apps/server/src/controllers/ChatController.ts

@@ -5,6 +5,7 @@ import {
   UpdateEventDTO,
   EventAction,
   GetMessagesOptions,
+  RecurringDeleteMode,
 } from "@calchat/shared";
 import { ChatService } from "../services";
 import { createLogger } from "../logging";
@@ -22,7 +23,10 @@ export class ChatController {
       const response = await this.chatService.processMessage(userId, data);
       res.json(response);
     } catch (error) {
-      log.error({ error, userId: req.user?.userId }, "Error processing message");
+      log.error(
+        { error, userId: req.user?.userId },
+        "Error processing message",
+      );
       res.status(500).json({ error: "Failed to process message" });
     }
   }
@@ -31,12 +35,22 @@ export class ChatController {
     try {
       const userId = req.user!.userId;
       const { conversationId, messageId } = req.params;
-      const { proposalId, action, event, eventId, updates } = req.body as {
+      const {
+        proposalId,
+        action,
+        event,
+        eventId,
+        updates,
+        deleteMode,
+        occurrenceDate,
+      } = req.body as {
         proposalId: string;
         action: EventAction;
         event?: CreateEventDTO;
         eventId?: string;
         updates?: UpdateEventDTO;
+        deleteMode?: RecurringDeleteMode;
+        occurrenceDate?: string;
       };
       const response = await this.chatService.confirmEvent(
         userId,
@@ -47,10 +61,15 @@ export class ChatController {
         event,
         eventId,
         updates,
+        deleteMode,
+        occurrenceDate,
       );
       res.json(response);
     } catch (error) {
-      log.error({ error, conversationId: req.params.conversationId }, "Error confirming event");
+      log.error(
+        { error, conversationId: req.params.conversationId },
+        "Error confirming event",
+      );
       res.status(500).json({ error: "Failed to confirm event" });
     }
   }
@@ -68,7 +87,10 @@ export class ChatController {
       );
       res.json(response);
     } catch (error) {
-      log.error({ error, conversationId: req.params.conversationId }, "Error rejecting event");
+      log.error(
+        { error, conversationId: req.params.conversationId },
+        "Error rejecting event",
+      );
       res.status(500).json({ error: "Failed to reject event" });
     }
   }
@@ -82,7 +104,10 @@ export class ChatController {
       const conversations = await this.chatService.getConversations(userId);
       res.json(conversations);
     } catch (error) {
-      log.error({ error, userId: req.user?.userId }, "Error getting conversations");
+      log.error(
+        { error, userId: req.user?.userId },
+        "Error getting conversations",
+      );
       res.status(500).json({ error: "Failed to get conversations" });
     }
   }
@@ -113,7 +138,10 @@ export class ChatController {
       if ((error as Error).message === "Conversation not found") {
         res.status(404).json({ error: "Conversation not found" });
       } else {
-        log.error({ error, conversationId: req.params.id }, "Error getting conversation");
+        log.error(
+          { error, conversationId: req.params.id },
+          "Error getting conversation",
+        );
         res.status(500).json({ error: "Failed to get conversation" });
       }
     }

apps/server/src/controllers/EventController.ts

@@ -1,4 +1,5 @@
 import { Response } from "express";
+import { RecurringDeleteMode } from "@calchat/shared";
 import { EventService } from "../services";
 import { createLogger } from "../logging";
 import { AuthenticatedRequest } from "./AuthMiddleware";
@@ -72,7 +73,10 @@ export class EventController {
       );
       res.json(events);
     } catch (error) {
-      log.error({ error, start: req.query.start, end: req.query.end }, "Error getting events by range");
+      log.error(
+        { error, start: req.query.start, end: req.query.end },
+        "Error getting events by range",
+      );
       res.status(500).json({ error: "Failed to get events" });
     }
   }
@@ -97,6 +101,38 @@ export class EventController {
 
   async delete(req: AuthenticatedRequest, res: Response): Promise<void> {
     try {
+      const { mode, occurrenceDate } = req.query as {
+        mode?: RecurringDeleteMode;
+        occurrenceDate?: string;
+      };
+
+      // If mode is specified, use deleteRecurring
+      if (mode) {
+        const result = await this.eventService.deleteRecurring(
+          req.params.id,
+          req.user!.userId,
+          mode,
+          occurrenceDate,
+        );
+
+        // For 'all' mode or when event was completely deleted, return 204
+        if (result === null && mode === "all") {
+          res.status(204).send();
+          return;
+        }
+
+        // For 'single' or 'future' modes, return updated event
+        if (result) {
+          res.json(result);
+          return;
+        }
+
+        // result is null but mode wasn't 'all' - event not found or was deleted
+        res.status(204).send();
+        return;
+      }
+
+      // Default behavior: delete completely
       const deleted = await this.eventService.delete(
         req.params.id,
         req.user!.userId,