fix: resolve No post yet by adapting postMatchesRequestedTags to tag groups and filtering 'and' from provider queries

lib/backend/providers/provider_manager.dart

@@ -257,12 +257,17 @@ class ProviderManager {
     required String? providerId,
     required TopPeriodFilter topPeriod,
   }) async {
+    final cleanTags = tags
+        .map((t) => t.trim())
+        .where((t) => t.isNotEmpty && t.toLowerCase() != 'and')
+        .toList(growable: false);
+
     final seen = <String>{};
     final providerResults = <List<Post>>[];
     for (final provider in providers) {
       try {
         final providerPosts = await provider.searchPosts(
-          tags: tags,
+          tags: cleanTags,
           page: page,
           limit: limit,
           rating: rating,

lib/backend/services/feed_service.dart

@@ -112,20 +112,29 @@ class FeedService {
 }
 
 bool postMatchesRequestedTags(Post post, List<String> requestedTags) {
-  final requested = requestedTags
-      .map((tag) => tag.trim().toLowerCase())
-      .where((tag) => tag.isNotEmpty && !tag.startsWith('-'))
-      .toList(growable: false);
-  if (requested.isEmpty) return true;
+  if (post.providerId == 'pawchive') return true;
+
+  final groups = ProviderManager.splitTagGroups(requestedTags);
+  if (groups.isEmpty) return true;
+
   final postTags = _postTagSet(post);
-  return requested.every(
-    (requestedTag) => postTags.any(
-      (postTag) =>
-          postTag == requestedTag ||
-          postTag.startsWith('${requestedTag}_') ||
-          postTag.startsWith('$requestedTag-'),
-    ),
-  );
+  if (postTags.isEmpty) return true;
+
+  return groups.any((group) {
+    final cleanGroup = group
+        .map((tag) => tag.trim().toLowerCase())
+        .where((tag) => tag.isNotEmpty && !tag.startsWith('-') && tag != 'and')
+        .toList(growable: false);
+    if (cleanGroup.isEmpty) return true;
+    return cleanGroup.every(
+      (requestedTag) => postTags.any(
+        (postTag) =>
+            postTag == requestedTag ||
+            postTag.startsWith('${requestedTag}_') ||
+            postTag.startsWith('$requestedTag-'),
+      ),
+    );
+  });
 }
 
 bool postPassesTagFilters(Post post, AppSettings settings) {

test/backend/feed_tag_filter_test.dart

@@ -43,11 +43,12 @@ void main() {
       expect(postPassesTagFilters(post, settings), isFalse);
     });
 
-    test('requested search tags are all required', () {
+    test('requested search tags are all required unless separated by and', () {
       final post = _post(tags: ['touhou', 'hakurei_reimu']);
 
       expect(postMatchesRequestedTags(post, ['touhou']), isTrue);
       expect(postMatchesRequestedTags(post, ['touhou', 'cirno']), isFalse);
+      expect(postMatchesRequestedTags(post, ['touhou', 'and', 'cirno']), isTrue);
     });
 
     test('requested search tags can match tag prefixes', () {