Fix series RRULE updates: editing 'all events' now properly updates original series RRULE

- Backend now updates RRULE when recurrence_count or recurrence_end_date parameters are provided
- Fixed update_entire_series() to modify COUNT/UNTIL instead of preserving original RRULE
- Added comprehensive RRULE parsing functions to extract existing frequency, interval, count, until, and BYDAY components
- Fixed frontend parameter mapping to pass recurrence parameters through update_series calls
- Resolves issue where changing recurring event from 5 to 7 occurrences kept original COUNT=5

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/services/calendar_service.rs

@@ -1678,6 +1678,9 @@ impl CalendarService {
         categories: String,
         reminder: String,
         recurrence: String,
+        recurrence_days: Vec<bool>,
+        recurrence_count: Option<u32>,
+        recurrence_until: Option<String>,
         calendar_path: Option<String>,
         update_scope: String,
         occurrence_date: Option<String>,
@@ -1706,10 +1709,10 @@ impl CalendarService {
             "categories": categories,
             "reminder": reminder,
             "recurrence": recurrence,
-            "recurrence_days": vec![false; 7], // Default - could be enhanced
-            "recurrence_interval": 1_u32, // Default interval
-            "recurrence_end_date": None as Option<String>, // No end date by default
-            "recurrence_count": None as Option<u32>, // No count limit by default
+            "recurrence_days": recurrence_days,
+            "recurrence_interval": 1_u32, // Default interval - could be enhanced to be a parameter
+            "recurrence_end_date": recurrence_until,
+            "recurrence_count": recurrence_count,
             "calendar_path": calendar_path,
             "update_scope": update_scope,
             "occurrence_date": occurrence_date