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/ocr_provider.dart

@@ -0,0 +1,43 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../services/ocr_service.dart';
+
+enum OcrStatus { none, processing, done, failed }
+
+final ocrServiceProvider = Provider<OcrService>((ref) => OcrService());
+
+/// Tracks local OCR processing status per note ID.
+///
+/// This map only ever holds an entry per note that has had OCR triggered in
+/// the current session. To keep it from growing without bound over a long
+/// session, prune terminal/stale entries via [OcrStatusX] (e.g. remove an
+/// entry once its result has been surfaced, or call [OcrStatusX.pruneOcr]
+/// after a sweep). Kept as a [StateProvider] so existing call sites that
+/// assign `ocrStatusProvider.notifier.state` continue to work.
+final ocrStatusProvider = StateProvider<Map<String, OcrStatus>>((ref) => {});
+
+/// Pruning helpers for [ocrStatusProvider] that keep its backing map bounded.
+extension OcrStatusX on Ref {
+  /// Removes the tracked status for [noteId] (e.g. when its note is deleted
+  /// or its result has been consumed by the UI).
+  void clearOcr(String noteId) {
+    final current = read(ocrStatusProvider);
+    if (!current.containsKey(noteId)) return;
+    read(ocrStatusProvider.notifier).state = Map<String, OcrStatus>.from(
+      current,
+    )..remove(noteId);
+  }
+
+  /// Drops all completed/failed entries, keeping only in-flight work so the
+  /// map stays bounded.
+  void pruneOcr() {
+    final current = read(ocrStatusProvider);
+    final next = <String, OcrStatus>{
+      for (final entry in current.entries)
+        if (entry.value == OcrStatus.processing) entry.key: entry.value,
+    };
+    if (next.length != current.length) {
+      read(ocrStatusProvider.notifier).state = next;
+    }
+  }
+}