Add provider tag suggestions and tag categories

lib/features/post/presentation/post_details_screen.dart

@@ -325,6 +325,9 @@ class _MobilePostPagerState extends State<_MobilePostPager> {
     super.initState();
     _currentIndex = widget.initialIndex;
     _controller = PageController(initialPage: widget.initialIndex);
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      _prefetchAround(widget.initialIndex);
+    });
   }
 
   @override
@@ -337,6 +340,9 @@ class _MobilePostPagerState extends State<_MobilePostPager> {
       if (_controller.hasClients) {
         _controller.jumpToPage(widget.initialIndex);
       }
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        _prefetchAround(widget.initialIndex);
+      });
     }
   }
 
@@ -353,6 +359,7 @@ class _MobilePostPagerState extends State<_MobilePostPager> {
       itemCount: widget.posts.length,
       onPageChanged: (index) {
         _currentIndex = index;
+        _prefetchAround(index);
         final post = widget.posts[index];
         WidgetsBinding.instance.addPostFrameCallback((_) {
           if (!mounted) return;
@@ -363,13 +370,52 @@ class _MobilePostPagerState extends State<_MobilePostPager> {
         });
       },
       itemBuilder: (context, index) {
-        return KeyedSubtree(
-          key: ValueKey(widget.posts[index].cacheKey),
-          child: widget.buildDetails(context, widget.posts[index]),
+        return _KeepAlivePostPage(
+          child: KeyedSubtree(
+            key: ValueKey(widget.posts[index].cacheKey),
+            child: widget.buildDetails(context, widget.posts[index]),
+          ),
         );
       },
     );
   }
+
+  void _prefetchAround(int index) {
+    for (final offset in [-1, 0, 1]) {
+      final target = index + offset;
+      if (target < 0 || target >= widget.posts.length) continue;
+      final post = widget.posts[target];
+      final urls = [
+        post.previewUrl,
+        post.sampleUrl,
+        if (post.fileType.toLowerCase().contains('gif')) post.fileUrl,
+      ].where((url) => url.trim().isNotEmpty).toSet();
+      for (final url in urls) {
+        precacheImage(NetworkImage(url), context);
+      }
+    }
+  }
+}
+
+class _KeepAlivePostPage extends StatefulWidget {
+  const _KeepAlivePostPage({required this.child});
+
+  final Widget child;
+
+  @override
+  State<_KeepAlivePostPage> createState() => _KeepAlivePostPageState();
+}
+
+class _KeepAlivePostPageState extends State<_KeepAlivePostPage>
+    with AutomaticKeepAliveClientMixin {
+  @override
+  bool get wantKeepAlive => true;
+
+  @override
+  Widget build(BuildContext context) {
+    super.build(context);
+    return widget.child;
+  }
 }
 
 class _CommentsSection extends ConsumerStatefulWidget {

lib/features/post/presentation/widgets/post_media_viewer.dart

@@ -214,11 +214,10 @@ class _PostMediaViewerState extends State<PostMediaViewer> {
   }
 
   List<String> _buildImageUrls(Post post) {
-    return {
-      post.sampleUrl,
-      post.fileUrl,
-      post.previewUrl,
-    }.where((url) => url.trim().isNotEmpty).toList();
+    final urls = post.fileType.toLowerCase().contains('gif')
+        ? [post.fileUrl, post.sampleUrl, post.previewUrl]
+        : [post.sampleUrl, post.fileUrl, post.previewUrl];
+    return urls.where((url) => url.trim().isNotEmpty).toSet().toList();
   }
 
   List<String> _buildVideoUrls(Post post) {

lib/features/post/presentation/widgets/post_tags_panel.dart

@@ -11,16 +11,66 @@ class PostTagsPanel extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Wrap(
-      spacing: 8,
-      runSpacing: 8,
+    final groups = _groups(post);
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
       children: [
-        for (final tag in post.tags.take(80))
-          TagChip(
-            tag: tag,
-            onTap: () => context.go('/?q=${Uri.encodeQueryComponent(tag)}'),
+        for (final entry in groups.entries) ...[
+          Padding(
+            padding: const EdgeInsets.only(top: 8, bottom: 6),
+            child: Text(
+              _label(entry.key),
+              style: Theme.of(context).textTheme.labelLarge,
+            ),
           ),
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
+            children: [
+              for (final tag in entry.value.take(80))
+                TagChip(
+                  tag: tag,
+                  onTap: () =>
+                      context.go('/?q=${Uri.encodeQueryComponent(tag)}'),
+                ),
+            ],
+          ),
+        ],
       ],
     );
   }
+
+  Map<String, List<String>> _groups(Post post) {
+    if (post.tagGroups.isNotEmpty) {
+      final ordered = <String, List<String>>{};
+      for (final key in [
+        'artist',
+        'character',
+        'copyright',
+        'species',
+        'meta',
+        'general',
+      ]) {
+        final tags = post.tagGroups[key];
+        if (tags != null && tags.isNotEmpty) ordered[key] = tags;
+      }
+      for (final entry in post.tagGroups.entries) {
+        ordered.putIfAbsent(entry.key, () => entry.value);
+      }
+      return ordered;
+    }
+    return {'general': post.tags};
+  }
+
+  String _label(String key) {
+    return switch (key) {
+      'artist' => 'Artist',
+      'character' => 'Character',
+      'copyright' => 'Copyright / Title',
+      'species' => 'Species',
+      'meta' => 'Meta',
+      'general' => 'General',
+      _ => 'Other',
+    };
+  }
 }