feat: support multiple event proposals in single AI response

- Change proposedChange to proposedChanges array in ChatMessage type
- Add unique id and individual respondedAction to each ProposedEventChange
- Implement arrow navigation UI for multiple proposals with "Event X von Y" counter
- Add updateProposalResponse() method for per-proposal confirm/reject tracking
- GPTAdapter now collects multiple tool call results into proposals array
- Add RRULE documentation to system prompt (separate events for different times)
- Fix RRULE parsing to strip RRULE: prefix if present
- Add log summarization for large args (conversationHistory, existingEvents)
- Keep proposedChanges logged in full for debugging AI issues

apps/server/src/utils/recurrenceExpander.ts

@@ -58,8 +58,10 @@ export function expandRecurringEvents(
 
     // Recurring event: parse RRULE and expand
     try {
+      // Strip RRULE: prefix if present (AI may include it)
+      const ruleString = event.recurrenceRule.replace(/^RRULE:/i, "");
       const rule = rrulestr(
-        `DTSTART:${formatRRuleDateString(startTime)}\nRRULE:${event.recurrenceRule}`,
+        `DTSTART:${formatRRuleDateString(startTime)}\nRRULE:${ruleString}`,
       );
 
       // Get occurrences within the range (using fake UTC dates)