feat: implement library view with Authors, Genres, and Series browsing

This commit implements a comprehensive library browsing feature:

- Add LibraryBrowserProvider with providers for authors, genres, and series data
- Create LibraryAuthorsPage with grid view of authors including images and book counts
- Create LibraryGenresPage with list view of all genres
- Create LibrarySeriesPage with list view of series and book counts
- Update LibraryBrowserPage navigation to route to the new views
- Add routes for /browser/authors, /browser/genres, and /browser/series
- Replace "Not Implemented" toasts with functional navigation

The implementation uses the Audiobookshelf API via shelfsdk to fetch:
- Authors list with metadata (getAuthors)
- Genres from library filter data (getFilterData)
- Series with pagination support (getSeries)

All views follow Material Design 3 patterns and include proper loading/error states.

lib/features/library_browser/view/library_series_page.dart

@@ -0,0 +1,105 @@
+import 'package:flutter/material.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:shelfsdk/audiobookshelf_api.dart';
+import 'package:vaani/api/library_browser_provider.dart';
+
+class LibrarySeriesPage extends HookConsumerWidget {
+  const LibrarySeriesPage({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final seriesAsync = ref.watch(librarySeriesProvider());
+
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Series'),
+      ),
+      body: seriesAsync.when(
+        data: (seriesResponse) {
+          if (seriesResponse == null || seriesResponse.results.isEmpty) {
+            return const Center(
+              child: Text('No series found'),
+            );
+          }
+
+          return ListView.builder(
+            padding: const EdgeInsets.symmetric(vertical: 8),
+            itemCount: seriesResponse.results.length,
+            itemBuilder: (context, index) {
+              final series = seriesResponse.results[index];
+              return SeriesListTile(series: series);
+            },
+          );
+        },
+        loading: () => const Center(
+          child: CircularProgressIndicator(),
+        ),
+        error: (error, stack) => Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              const Icon(Icons.error_outline, size: 48, color: Colors.red),
+              const SizedBox(height: 16),
+              Text('Error loading series: $error'),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+class SeriesListTile extends StatelessWidget {
+  const SeriesListTile({
+    super.key,
+    required this.series,
+  });
+
+  final Series series;
+
+  @override
+  Widget build(BuildContext context) {
+    // Extract series data based on variant
+    final String seriesName = series.name;
+    final int? numBooks = series.maybeMap(
+      numBooks: (s) => s.numBooks,
+      books: (s) => s.books.length,
+      orElse: () => null,
+    );
+
+    return Card(
+      margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
+      child: ListTile(
+        leading: Container(
+          width: 48,
+          height: 48,
+          decoration: BoxDecoration(
+            color: Theme.of(context).colorScheme.secondaryContainer,
+            borderRadius: BorderRadius.circular(8),
+          ),
+          child: Icon(
+            Icons.list,
+            color: Theme.of(context).colorScheme.onSecondaryContainer,
+          ),
+        ),
+        title: Text(
+          seriesName,
+          style: Theme.of(context).textTheme.titleMedium,
+        ),
+        subtitle: numBooks != null
+            ? Text('$numBooks ${numBooks == 1 ? 'book' : 'books'}')
+            : null,
+        trailing: const Icon(Icons.chevron_right),
+        onTap: () {
+          // TODO: Navigate to series detail page
+          ScaffoldMessenger.of(context).showSnackBar(
+            SnackBar(
+              content: Text('Tapped on $seriesName'),
+              duration: const Duration(seconds: 1),
+            ),
+          );
+        },
+      ),
+    );
+  }
+}