feat(app): stabilize recommendation flow

lib/presentation/providers/location_provider.dart

@@ -1,3 +1,4 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:geolocator/geolocator.dart';
 import 'package:lunchpick/core/utils/app_logger.dart';
@@ -69,13 +70,31 @@ final currentLocationProvider = FutureProvider<Position?>((ref) async {
 });
 
 /// 위치 스트림 Provider
-final locationStreamProvider = StreamProvider<Position>((ref) {
-  return Geolocator.getPositionStream(
-    locationSettings: const LocationSettings(
-      accuracy: LocationAccuracy.high,
-      distanceFilter: 10, // 10미터 이상 이동 시 업데이트
-    ),
-  );
+final locationStreamProvider = StreamProvider<Position>((ref) async* {
+  if (kIsWeb) {
+    AppLogger.debug('[location] web detected, emit fallback immediately');
+    yield defaultPosition();
+    return;
+  }
+
+  final status = await Permission.location.status;
+  if (!status.isGranted) {
+    AppLogger.debug('[location] permission not granted, emit fallback');
+    yield defaultPosition();
+    return;
+  }
+
+  try {
+    yield* Geolocator.getPositionStream(
+      locationSettings: const LocationSettings(
+        accuracy: LocationAccuracy.high,
+        distanceFilter: 10, // 10미터 이상 이동 시 업데이트
+      ),
+    );
+  } catch (_) {
+    AppLogger.error('[location] position stream failed, emit fallback');
+    yield defaultPosition();
+  }
 });
 
 /// 초기 3초 내 위치를 가져오지 못하면 기본 좌표를 우선 반환하고,
@@ -83,20 +102,30 @@ final locationStreamProvider = StreamProvider<Position>((ref) {
 final currentLocationWithFallbackProvider = StreamProvider<Position>((
   ref,
 ) async* {
-  final initial = await Future.any([
-    ref
-        .watch(currentLocationProvider.future)
-        .then((pos) => pos ?? defaultPosition()),
-    Future<Position>.delayed(
-      const Duration(seconds: 3),
-      () => defaultPosition(),
-    ),
-  ]).catchError((_) => defaultPosition());
+  AppLogger.debug('[location] emit fallback immediately (safe start)');
+  // 웹/권한 거부 상황에서는 즉시 기본 좌표를 먼저 흘려보내 리스트 로딩을 막는다.
+  final fallback = defaultPosition();
+  yield fallback;
 
-  yield initial;
+  final initial = await Future.any([
+    ref.watch(currentLocationProvider.future).then((pos) => pos ?? fallback),
+    Future<Position>.delayed(const Duration(seconds: 3), () => fallback),
+  ]).catchError((_) => fallback);
+
+  if (initial.latitude != fallback.latitude ||
+      initial.longitude != fallback.longitude) {
+    AppLogger.debug(
+      '[location] resolved initial position: '
+      '${initial.latitude}, ${initial.longitude}',
+    );
+    yield initial;
+  } else {
+    AppLogger.debug('[location] initial resolved to fallback');
+  }
 
   yield* ref.watch(locationStreamProvider.stream).handleError((_) {
     // 스트림 오류는 무시하고 마지막 위치를 유지
+    AppLogger.error('[location] stream error, keeping last position');
   });
 });