Sidebar fixes: multi-group payments, cycle range, num_positions, all tandas

- groups-advanced-system.html: 4 sidebar fixes (payments list, cycle range, num_positions, all tandas)
- css/groups-page.css: payment list CSS (.gs-payments-list, .gs-pay-item)
- Cache: groups-page.css?v=2.8

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: INDIGOAZUL

css/groups-page.css

@@ -1318,40 +1318,58 @@
             letter-spacing: 0.3px;
         }
 
-        /* Next payment */
-        .gs-next-payment {
-            text-align: center;
+        /* Next payments list */
+        .gs-payments-list {
+            display: flex;
+            flex-direction: column;
+            max-height: 240px;
+            overflow-y: auto;
+        }
+        .gs-pay-item {
+            display: flex;
+            justify-content: space-between;
+            align-items: flex-start;
+            padding: 8px 0;
+            border-bottom: 1px solid rgba(255,255,255,0.04);
+        }
+        .gs-pay-item:last-child {
+            border-bottom: none;
+        }
+        .gs-pay-item-left {
+            flex: 1;
+            min-width: 0;
+        }
+        .gs-pay-item-right {
+            text-align: right;
+            flex-shrink: 0;
+            margin-left: 8px;
         }
         .gs-next-group {
-            font-size: 0.82rem;
+            font-size: 0.78rem;
             color: #e2e8f0;
             font-weight: 500;
-            margin-bottom: 6px;
+            margin-bottom: 2px;
             white-space: nowrap;
             overflow: hidden;
             text-overflow: ellipsis;
         }
-        .gs-next-details {
-            display: flex;
-            justify-content: space-between;
-            align-items: center;
-            margin-bottom: 6px;
-        }
         .gs-next-amount {
-            font-size: 1.1rem;
+            font-size: 0.85rem;
             font-weight: 700;
             color: #f59e0b;
+            margin-bottom: 2px;
         }
         .gs-next-date {
-            font-size: 0.75rem;
+            font-size: 0.7rem;
             color: #64748b;
         }
         .gs-next-countdown {
-            font-size: 0.72rem;
+            font-size: 0.65rem;
             font-weight: 600;
-            padding: 4px 10px;
+            padding: 2px 8px;
             border-radius: 6px;
             display: inline-block;
+            margin-top: 2px;
         }
         .gs-next-countdown.gs-countdown-ok {
             background: rgba(0,255,255,0.1);