Phase 3.5: Mitra Chat Request History (backend route + mitra app screens)

Replaces the home-screen pending-requests banner with a "Riwayat
Permintaan" CTA that opens a list of the mitra's last 20 chat requests
(any status). Pending rows pin to the top; non-pending rows open a
read-only detail screen with a "Lihat percakapan" CTA on accepted rows.

Backend:
- New service `getRecentRequestsForMitra(mitraId, { limit })` capped at
  20, pending pinned via `(response IS NULL AND status='pending_acceptance')
  DESC`. Customer call_name returned verbatim, with `'Anonim'` only as
  null-safety fallback (no anonymity-flag masking — see project memory).
- New route `GET /api/mitra/chat-requests/recent`. Strictly per-mitra
  scoped via the existing `resolveMitra` preHandler.

Mitra app:
- New `RequestResponse` enum in core/constants.dart.
- New Riverpod notifier `requestHistoryProvider` (AsyncValue<List<...>>,
  keepAlive) — pull-to-refresh + screen-mount fetch only, no WS.
- Two new screens (history list + detail) and two new GoRoutes.
- Home screen: `_PendingRequestsBanner` removed → `_RequestHistoryButton`
  Card with red count badge. Live count comes from the existing
  chatRequestProvider so nothing changes about the WS-driven badge math.

Plan + acceptance criteria in requirement/phase3.5-plan.md. flutter
analyze clean (zero new issues). Backend smoke-tested against real DB.
Real-device E2E pending.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mitra_app/lib/features/home/home_screen.dart

@@ -57,7 +57,6 @@ class HomeScreen extends ConsumerWidget {
             const SizedBox(height: 32),
             const _StatusToggle(),
             const SizedBox(height: 16),
-            const _PendingRequestsBanner(),
             const _ActiveSessionsButton(),
           ],
         ),
@@ -125,51 +124,6 @@ class _StatusToggle extends ConsumerWidget {
   }
 }
 
-class _PendingRequestsBanner extends ConsumerWidget {
-  const _PendingRequestsBanner();
-
-  @override
-  Widget build(BuildContext context, WidgetRef ref) {
-    final requestState = ref.watch(chatRequestProvider);
-    final count = ref.read(chatRequestProvider.notifier).activeRequestCount;
-
-    if (count == 0) return const SizedBox.shrink();
-
-    final isShowingOverlay = requestState is ChatRequestIncomingData ||
-        requestState is ChatRequestStaleData;
-
-    return Padding(
-      padding: const EdgeInsets.only(bottom: 16),
-      child: Card(
-        color: Colors.blue.shade50,
-        child: ListTile(
-          leading: Badge(
-            label: Text('$count'),
-            child: const Icon(Icons.notifications_active, color: Colors.blue),
-          ),
-          title: Text(
-            '$count permintaan chat menunggu',
-            style: const TextStyle(fontWeight: FontWeight.bold),
-          ),
-          subtitle: isShowingOverlay
-              ? null
-              : const Text('Ketuk untuk melihat'),
-          onTap: isShowingOverlay
-              ? null
-              : () {
-                  // Re-advance queue to show the next request overlay
-                  final notifier = ref.read(chatRequestProvider.notifier);
-                  if (requestState is ChatRequestListeningData) {
-                    // Requests are queued but none is displayed — trigger next
-                    notifier.ignore();
-                  }
-                },
-        ),
-      ),
-    );
-  }
-}
-
 class _ActiveSessionsButton extends ConsumerWidget {
   const _ActiveSessionsButton();
 
@@ -192,6 +146,7 @@ class _ActiveSessionsButton extends ConsumerWidget {
             onTap: () => context.push('/sessions'),
           ),
         ),
+        const _RequestHistoryButton(),
         Card(
           child: ListTile(
             leading: const Icon(Icons.history),
@@ -204,3 +159,56 @@ class _ActiveSessionsButton extends ConsumerWidget {
     );
   }
 }
+
+class _RequestHistoryButton extends ConsumerWidget {
+  const _RequestHistoryButton();
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    // Watch state to rebuild when requests arrive/clear; count comes from
+    // the notifier which tracks both displayed + queued requests.
+    ref.watch(chatRequestProvider);
+    final count = ref.read(chatRequestProvider.notifier).activeRequestCount;
+
+    final hasPending = count > 0;
+    final trailing = hasPending
+        ? Row(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Container(
+                padding:
+                    const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
+                decoration: BoxDecoration(
+                  color: Colors.red,
+                  borderRadius: BorderRadius.circular(999),
+                ),
+                child: Text(
+                  '$count',
+                  style: const TextStyle(
+                    color: Colors.white,
+                    fontWeight: FontWeight.bold,
+                    fontSize: 12,
+                  ),
+                ),
+              ),
+              const SizedBox(width: 4),
+              const Icon(Icons.chevron_right),
+            ],
+          )
+        : const Icon(Icons.chevron_right);
+
+    return Card(
+      child: ListTile(
+        leading: const Icon(Icons.notifications_outlined),
+        title: const Text('Riwayat Permintaan'),
+        subtitle: Text(
+          hasPending
+              ? '$count permintaan baru'
+              : 'Lihat permintaan chat sebelumnya',
+        ),
+        trailing: trailing,
+        onTap: () => context.push('/chat/requests/history'),
+      ),
+    );
+  }
+}