feat: zoom percentage badge at bottom center (v1.7.1)

- Percentage shown between the prev/next buttons, together with the hover
  controls, on a translucent background.
- Value is the on-screen scale relative to the image's real pixel size
  (100% = 1:1); updated on wheel zoom, fill/fit toggle, image change and
  window resize.
- Pixel-size header parsing moved to lib/services/image_header.dart, shared
  with the settings file-properties panel.
- dist: 1.7.1 .deb replaces the tracked 1.7.0 package.

lib/widgets/image_canvas.dart

@@ -6,11 +6,15 @@ import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import '../l10n/app_localizations.dart';
 import '../services/crop_save_service.dart';
+import '../services/image_header.dart';
 import '../services/window_persistence.dart';
 
 class ImageCanvas extends StatefulWidget {
   final String filePath;
-  const ImageCanvas({super.key, required this.filePath});
+
+  /// Görüntünün gerçek piksel boyutuna göre ölçek yüzdesi (100% = 1:1).
+  final ValueNotifier<double>? zoomPercent;
+  const ImageCanvas({super.key, required this.filePath, this.zoomPercent});
   @override
   State<ImageCanvas> createState() => ImageCanvasState();
 }
@@ -47,6 +51,44 @@ class ImageCanvasState extends State<ImageCanvas> {
   Size _imageSize = Size.zero;
   static const int _downsampleTarget = 2048;
 
+  // ── Gerçek piksel boyutu + zoom yüzdesi ──
+  Size? _origSize;
+  bool _zoomSyncScheduled = false;
+
+  /// Yüzdeyi bir sonraki kare sonunda yayınla (build sırasında setState tetiklememek için).
+  void _syncZoom() {
+    if (_zoomSyncScheduled) return;
+    _zoomSyncScheduled = true;
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      _zoomSyncScheduled = false;
+      if (!mounted) return;
+      final n = widget.zoomPercent;
+      if (n == null) return;
+      final v = _zoomPercentValue();
+      if (n.value != v) n.value = v;
+    });
+  }
+
+  /// Ekrandaki ölçeğin görüntünün gerçek piksel boyutuna oranı (100% = 1:1).
+  double _zoomPercentValue() {
+    final o = _origSize;
+    if (o == null || o.isEmpty || _vpSize.isEmpty) return _sc * 100;
+    final double ratio;
+    if (_isFilled) {
+      // cover: kutu viewport, boya ölçeği max oran
+      ratio = math.max(_vpSize.width / o.width, _vpSize.height / o.height);
+    } else {
+      // contain: yerleşmiş görüntü kutusu (downsample sınırı dahil) → gerçek ölçek
+      final box = _imageKey.currentContext?.findRenderObject() as RenderBox?;
+      if (box != null && box.hasSize && box.size.width > 0) {
+        ratio = box.size.width / o.width;
+      } else {
+        ratio = math.min(_vpSize.width / o.width, _vpSize.height / o.height);
+      }
+    }
+    return _sc * ratio * 100;
+  }
+
   // ── Kare hızına eşitlenmiş render tick ──
   final ValueNotifier<int> _renderTick = ValueNotifier(0);
   bool _frameScheduled = false;
@@ -128,8 +170,10 @@ class ImageCanvasState extends State<ImageCanvas> {
   @override
   void initState() {
     super.initState();
+    _origSize = pixelSizeOfFile(widget.filePath);
     HardwareKeyboard.instance.addHandler(_onHardwareKey);
     _startWarmup();
+    _syncZoom();
   }
 
   /// İlk kullanım shader derlemesini açılışa çek: gizli katmanda sırayla
@@ -189,6 +233,7 @@ class ImageCanvasState extends State<ImageCanvas> {
   void didUpdateWidget(ImageCanvas old) {
     super.didUpdateWidget(old);
     if (old.filePath != widget.filePath) {
+      _origSize = pixelSizeOfFile(widget.filePath);
       _cachedFileImage?.evict();
       _cachedProvider?.evict();
       _cachedFileImage = null;
@@ -207,6 +252,7 @@ class ImageCanvasState extends State<ImageCanvas> {
     _usingFullRes = false;
     _imageSize = Size.zero;
     _markRenderDirty();
+    _syncZoom();
   }
 
   void _toggleFillFit() {
@@ -215,6 +261,7 @@ class ImageCanvasState extends State<ImageCanvas> {
     _flipH = false;
     WindowPersistence.saveFilled(_isFilled);
     _markRenderDirty();
+    _syncZoom();
   }
 
   /// Ctrl+R: sağ çift tık gibi efektleri sıfırlar ve yatay aynalar; tekrar basınca geri alır.
@@ -250,6 +297,7 @@ class ImageCanvasState extends State<ImageCanvas> {
     _checkFullResSwap();
     _clamp();
     _markRenderDirty();
+    _syncZoom();
   }
 
   void _onPanUpdate(DragUpdateDetails d) {
@@ -502,7 +550,10 @@ class ImageCanvasState extends State<ImageCanvas> {
   Widget build(BuildContext context) {
     return LayoutBuilder(
       builder: (context, constraints) {
-        _vpSize = constraints.biggest;
+        if (constraints.biggest != _vpSize) {
+          _vpSize = constraints.biggest;
+          _syncZoom();
+        }
         _clamp();
         return RepaintBoundary(
           child: ValueListenableBuilder<int>(