feat: add EditEventScreen with calendar and chat mode support

Add a unified event editor that works in two modes:
- Calendar mode: Create/edit events directly via EventService API
- Chat mode: Edit AI-proposed events before confirming them

The chat mode allows users to modify proposed events (title, time,
recurrence) and persists changes both locally and to the server.

New components: DateTimePicker, ScrollableDropdown, useDropdownPosition
New API: PUT /api/chat/messages/:messageId/proposal

apps/client/src/components/ProposedEventCard.tsx

@@ -1,25 +1,31 @@
 import { View, Text, Pressable } from "react-native";
 import { Feather } from "@expo/vector-icons";
-import { ProposedEventChange, parseRRule, formatDate } from "@calchat/shared";
+import { ProposedEventChange, formatDate } from "@calchat/shared";
+import { rrulestr } from "rrule";
 import { useThemeStore } from "../stores/ThemeStore";
 import { EventCardBase } from "./EventCardBase";
 
 type ProposedEventCardProps = {
   proposedChange: ProposedEventChange;
-  onConfirm: () => void;
+  onConfirm: (proposal: ProposedEventChange) => void;
   onReject: () => void;
+  onEdit?: (proposal: ProposedEventChange) => void;
 };
 
-const ConfirmRejectButtons = ({
+const ActionButtons = ({
   isDisabled,
   respondedAction,
+  showEdit,
   onConfirm,
   onReject,
+  onEdit,
 }: {
   isDisabled: boolean;
   respondedAction?: "confirm" | "reject";
+  showEdit: boolean;
   onConfirm: () => void;
   onReject: () => void;
+  onEdit?: () => void;
 }) => {
   const { theme } = useThemeStore();
   return (
@@ -56,6 +62,19 @@ const ConfirmRejectButtons = ({
           Ablehnen
         </Text>
       </Pressable>
+      {showEdit && onEdit && (
+        <Pressable
+          onPress={onEdit}
+          className="py-2 px-3 rounded-lg items-center"
+          style={{
+            backgroundColor: theme.secondaryBg,
+            borderWidth: 1,
+            borderColor: theme.borderPrimary,
+          }}
+        >
+          <Feather name="edit-2" size={18} color={theme.textPrimary} />
+        </Pressable>
+      )}
     </View>
   );
 };
@@ -64,6 +83,7 @@ export const ProposedEventCard = ({
   proposedChange,
   onConfirm,
   onReject,
+  onEdit,
 }: ProposedEventCardProps) => {
   const { theme } = useThemeStore();
   const event = proposedChange.event;
@@ -79,7 +99,7 @@ export const ProposedEventCard = ({
   const newUntilDate =
     proposedChange.action === "update" &&
     event?.recurrenceRule &&
-    parseRRule(event.recurrenceRule)?.until;
+    rrulestr(event.recurrenceRule).options.until;
 
   if (!event) {
     return null;
@@ -93,7 +113,7 @@ export const ProposedEventCard = ({
         startTime={event.startTime}
         endTime={event.endTime}
         description={event.description}
-        isRecurring={event.isRecurring}
+        isRecurring={!!event.recurrenceRule}
       >
         {/* Show new exception date for delete/single actions */}
         {newExceptionDate && (
@@ -123,11 +143,13 @@ export const ProposedEventCard = ({
             </Text>
           </View>
         )}
-        <ConfirmRejectButtons
+        <ActionButtons
           isDisabled={isDisabled}
           respondedAction={proposedChange.respondedAction}
-          onConfirm={onConfirm}
+          showEdit={proposedChange.action !== "delete" && !isDisabled}
+          onConfirm={() => onConfirm(proposedChange)}
           onReject={onReject}
+          onEdit={onEdit ? () => onEdit(proposedChange) : undefined}
         />
       </EventCardBase>
     </View>