feat: enable proxy toggle on quick deploy, event log clearing, and UX fixes

- Add enable_proxy toggle to Quick Deploy form (defaults to on)
- Add DELETE /api/events/log/{id} and DELETE /api/events/log endpoints
- Add Clear All button with confirmation on Events page
- Rename "NPM Proxy" to "Enable Proxy" on stage form (provider-agnostic)
- Fix polling interval validation (min 60s) and number input trim errors
- Fix domain field no longer required in settings

internal/store/eventlog.go

@@ -153,6 +153,28 @@ func (s *Store) GetEventStats() (EventLogStats, error) {
 }
 
 // PruneEvents deletes event log entries older than the given number of days.
+// DeleteEvent removes a single event log entry by ID.
+func (s *Store) DeleteEvent(id int64) error {
+	result, err := s.db.Exec(`DELETE FROM event_log WHERE id = ?`, id)
+	if err != nil {
+		return fmt.Errorf("delete event: %w", err)
+	}
+	n, _ := result.RowsAffected()
+	if n == 0 {
+		return fmt.Errorf("event %d: %w", id, ErrNotFound)
+	}
+	return nil
+}
+
+// ClearAllEvents removes all event log entries.
+func (s *Store) ClearAllEvents() (int64, error) {
+	result, err := s.db.Exec(`DELETE FROM event_log`)
+	if err != nil {
+		return 0, fmt.Errorf("clear events: %w", err)
+	}
+	return result.RowsAffected()
+}
+
 func (s *Store) PruneEvents(olderThanDays int) (int64, error) {
 	if olderThanDays < 1 {
 		return 0, fmt.Errorf("prune events: olderThanDays must be >= 1, got %d", olderThanDays)