feat: add HTML providers for Realbooru and Paheal, hidden posts screen, and UI/search enhancements

lib/features/search/presentation/search_controller.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../../../backend/backend.dart';
@@ -8,8 +10,12 @@ final searchControllerProvider =
     AsyncNotifierProvider<SearchController, SearchState>(SearchController.new);
 
 class SearchController extends AsyncNotifier<SearchState> {
+  Timer? _suggestionDebounce;
+  int _suggestionRequestId = 0;
+
   @override
   Future<SearchState> build() async {
+    ref.onDispose(() => _suggestionDebounce?.cancel());
     final recent = await _recent();
     return SearchState(recent: recent);
   }
@@ -17,18 +23,42 @@ class SearchController extends AsyncNotifier<SearchState> {
   Future<void> updateQuery(String query) async {
     final lastToken =
         query.trim().isEmpty ? '' : query.trim().split(RegExp(r'\s+')).last;
-    final suggestionsResult = await ref
-        .read(searchServiceProvider)
-        .autocompleteDetailed(lastToken, limit: 16);
-    final suggestions = suggestionsResult is Success<List<TagSuggestion>>
-        ? suggestionsResult.data
-        : <TagSuggestion>[];
+    final requestId = ++_suggestionRequestId;
+    _suggestionDebounce?.cancel();
+    if (lastToken.isEmpty) {
+      state = AsyncData(
+        (state.value ?? const SearchState()).copyWith(
+          query: query,
+          suggestions: const [],
+        ),
+      );
+      return;
+    }
     state = AsyncData(
       (state.value ?? const SearchState()).copyWith(
         query: query,
-        suggestions: suggestions,
       ),
     );
+    _suggestionDebounce = Timer(const Duration(milliseconds: 280), () async {
+      final suggestionsResult = await ref
+          .read(searchServiceProvider)
+          .autocompleteDetailed(lastToken, limit: 16);
+      if (requestId != _suggestionRequestId) return;
+      final normalizedToken = lastToken.trim().toLowerCase();
+      final suggestions = suggestionsResult is Success<List<TagSuggestion>>
+          ? suggestionsResult.data
+              .where((item) => item.name.toLowerCase().startsWith(
+                    normalizedToken,
+                  ))
+              .toList(growable: false)
+          : <TagSuggestion>[];
+      state = AsyncData(
+        (state.value ?? const SearchState()).copyWith(
+          query: query,
+          suggestions: suggestions,
+        ),
+      );
+    });
   }
 
   Future<void> clearHistory() async {