Fix bugs across app + server, optimize UI/UX, add Gitea CI

Bug fixes (Flutter):
- Wrap multi-statement DB writes (insert/update/delete note, deleteDocument,
  deletePageData, OCR FTS merge, migrations) in transactions to prevent data
  loss on interruption and a read-modify-write FTS race.
- Fix PdfDocument leaks on exception (try/finally dispose) and preserve image
  aspect ratio when stamping images onto PDF pages.
- Guard file-picker against empty selection (was .single -> crash).
- Fix eraser ConcurrentModificationError and unmodifiable-list crash on PDF
  pages; capture page synchronously on save to stop wrong-page data loss.
- Fix Riverpod DB-not-ready races, broken pull-to-refresh, settings load race,
  and search N+1; transform stored annotations on PDF page rotation.
- Normalize pen pressure for devices without a pressure range.
- PPT: single source of truth for slide strokes so ink displays and exports.

UI/UX:
- Material 3 typography, theme-aware colors (dark-mode fixes), hover cursors
  and right-click/visible actions on desktop, keyboard shortcuts (undo/redo/
  save/find), toolbar overflow handling, friendlier empty states, semantic OCR
  status badges, relative timestamps, 1-based page indicators, large-deck PPT
  navigation, and a scratchpad-scope label in split view.

Server (optional backend):
- Persist JWT secret (was per-process random), block path traversal in storage,
  fix CORS '*'+credentials, add OCR job ownership checks, last-writer-wins sync
  guard, constant-time login, and split out heavy OCR deps so the API/tests run
  without them.

CI: Gitea workflows for format+analyze+test (Linux, system sqlite) and a
Windows release build; pristine `flutter analyze`, all Flutter and server tests
green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/providers/document_provider.dart

@@ -0,0 +1,62 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:uuid/uuid.dart';
+
+import '../models/document.dart';
+import '../services/database_service.dart';
+import 'note_provider.dart';
+
+const _uuid = Uuid();
+
+final documentListProvider =
+    AsyncNotifierProvider<DocumentListNotifier, List<Document>>(
+      DocumentListNotifier.new,
+    );
+
+class DocumentListNotifier extends AsyncNotifier<List<Document>> {
+  Future<DatabaseService> get _db => ref.read(databaseServiceProvider.future);
+
+  @override
+  Future<List<Document>> build() async {
+    final db = await _db;
+    return db.getAllDocuments();
+  }
+
+  /// Reloads documents from the database and publishes the result to [state]
+  /// so the UI rebuilds. Used by pull-to-refresh.
+  Future<void> loadDocuments() async {
+    state = const AsyncLoading();
+    state = await AsyncValue.guard(() async {
+      final db = await _db;
+      return db.getAllDocuments();
+    });
+  }
+
+  Future<Document> addDocument({
+    required String filename,
+    required String docType,
+    required String filePath,
+    int pageCount = 0,
+  }) async {
+    final db = await _db;
+    final now = DateTime.now();
+    final document = Document(
+      id: _uuid.v4(),
+      filename: filename,
+      docType: docType,
+      filePath: filePath,
+      pageCount: pageCount,
+      createdAt: now,
+      updatedAt: now,
+    );
+    await db.insertDocument(document);
+    state = AsyncData([document, ...state.value ?? []]);
+    return document;
+  }
+
+  Future<void> removeDocument(String id) async {
+    final db = await _db;
+    await db.deleteDocument(id);
+    final current = state.value ?? [];
+    state = AsyncData(current.where((d) => d.id != id).toList());
+  }
+}