feat: right-click contrast, Ctrl+saturation, Shift+rotate filters

- Add ColorFilter.matrix (row-major) for saturation and contrast
- Saturation: 0=grayscale, 1=normal, 2=oversaturated (luminance-weighted)
- Contrast: standard contrast matrix (pivot at 0.5)
- Keyboard modifier tracking via HardwareKeyboard.addHandler
- Right-click + vertical drag: contrast (0-2)
- Ctrl + right-click + vertical drag: saturation (0-2)
- Shift + right-click + vertical drag: rotate
- Right double-click: reset all values
- Update install.sh to check debug/ bundle before release/
- Update .deb package with new release build

lib/widgets/image_canvas.dart

@@ -1,6 +1,8 @@
 import 'dart:io';
+import 'dart:math' as math;
 import 'package:flutter/material.dart';
 import 'package:flutter/gestures.dart';
+import 'package:flutter/services.dart';
 
 class ImageCanvas extends StatefulWidget {
   final String filePath;
@@ -15,10 +17,27 @@ class _ImageCanvasState extends State<ImageCanvas> {
   double _tx = 0, _ty = 0, _sc = 1.0;
   Size _vpSize = Size.zero;
 
+  // ── Görüntü ayarları ──
+  double _angle = 0;
+  double _contrast = 1.0;
+  double _saturation = 1.0;
+
+  // ── Gesture tracking ──
+  String _interactionMode = 'none'; // 'contrast' | 'rotate' | 'saturation'
+  Offset _pointerDownPos = Offset.zero;
+  double _startAngle = 0;
+  double _startContrast = 1.0;
+  double _startSaturation = 1.0;
+  DateTime? _lastRightTapTime;
+  Offset _lastRightTapPos = Offset.zero;
+
+  // ── Klavye modifier tracking ──
+  bool _ctrlPressed = false;
+  bool _shiftPressed = false;
+
   void _clamp() {
     if (_vpSize.width <= 0 || _vpSize.height <= 0) return;
     if (_isFilled) {
-      // Fill mode: viewport tabanli clamp
       final double w = _vpSize.width * _sc;
       final double h = _vpSize.height * _sc;
       if (w >= _vpSize.width) {
@@ -31,7 +50,6 @@ class _ImageCanvasState extends State<ImageCanvas> {
       } else { if (_ty != 0) _ty = 0; }
       return;
     }
-    // Fit mode: resmin gercek boyutuna gore clamp (letterbox dahil)
     double m = 0, n = 0;
     double w = _vpSize.width * _sc;
     double h = _vpSize.height * _sc;
@@ -77,17 +95,60 @@ class _ImageCanvasState extends State<ImageCanvas> {
     }
   }
 
+  @override
+  void initState() {
+    super.initState();
+    HardwareKeyboard.instance.addHandler(_onHardwareKey);
+  }
+
+  @override
+  void dispose() {
+    HardwareKeyboard.instance.removeHandler(_onHardwareKey);
+    super.dispose();
+  }
+
+  bool _onHardwareKey(KeyEvent event) {
+    final key = event.logicalKey;
+    if (event is KeyDownEvent) {
+      if (key == LogicalKeyboardKey.controlLeft ||
+          key == LogicalKeyboardKey.controlRight) {
+        _ctrlPressed = true;
+      } else if (key == LogicalKeyboardKey.shiftLeft ||
+                 key == LogicalKeyboardKey.shiftRight) {
+        _shiftPressed = true;
+      }
+    } else if (event is KeyUpEvent) {
+      if (key == LogicalKeyboardKey.controlLeft ||
+          key == LogicalKeyboardKey.controlRight) {
+        _ctrlPressed = false;
+      } else if (key == LogicalKeyboardKey.shiftLeft ||
+                 key == LogicalKeyboardKey.shiftRight) {
+        _shiftPressed = false;
+      }
+    }
+    return false;
+  }
+
   @override
   void didUpdateWidget(ImageCanvas old) {
     super.didUpdateWidget(old);
     if (old.filePath != widget.filePath) _resetView();
   }
+
   void _resetView() {
-    setState(() { _tx = 0; _ty = 0; _sc = 1.0; _isFilled = true; _vpSize = Size.zero; });
+    setState(() {
+      _tx = 0; _ty = 0; _sc = 1.0; _isFilled = true; _vpSize = Size.zero;
+      _angle = 0; _contrast = 1.0; _saturation = 1.0;
+    });
   }
+
   void _toggleFillFit() {
-    setState(() { _isFilled = !_isFilled; _tx = 0; _ty = 0; _sc = 1.0; _vpSize = Size.zero; });
+    setState(() {
+      _isFilled = !_isFilled; _tx = 0; _ty = 0; _sc = 1.0; _vpSize = Size.zero;
+      _angle = 0; _contrast = 1.0; _saturation = 1.0;
+    });
   }
+
   void _handleDoubleTap() => _toggleFillFit();
 
   void _handleScroll(PointerScrollEvent e) {
@@ -113,6 +174,95 @@ class _ImageCanvasState extends State<ImageCanvas> {
     setState(() {});
   }
 
+  void _onPointerDown(PointerDownEvent e) {
+    if (e.buttons != kSecondaryMouseButton) return;
+
+    _pointerDownPos = e.localPosition;
+
+    final now = DateTime.now();
+    if (_lastRightTapTime != null &&
+        now.difference(_lastRightTapTime!) < const Duration(milliseconds: 400) &&
+        (e.localPosition - _lastRightTapPos).distance < 20) {
+      setState(() {
+        _angle = 0;
+        _contrast = 1.0;
+        _saturation = 1.0;
+        _interactionMode = 'none';
+      });
+      _lastRightTapTime = null;
+      return;
+    }
+    _lastRightTapTime = now;
+    _lastRightTapPos = e.localPosition;
+
+    if (_ctrlPressed) {
+      _interactionMode = 'saturation';
+      _startSaturation = _saturation;
+    } else if (_shiftPressed) {
+      _interactionMode = 'rotate';
+      _startAngle = _angle;
+    } else {
+      _interactionMode = 'contrast';
+      _startContrast = _contrast;
+    }
+  }
+
+  void _onPointerMove(PointerMoveEvent e) {
+    if (e.buttons != kSecondaryMouseButton) return;
+
+    final dy = e.localPosition.dy - _pointerDownPos.dy;
+
+    switch (_interactionMode) {
+      case 'contrast':
+        setState(() {
+          _contrast = (_startContrast + dy * 0.005).clamp(0.0, 2.0);
+        });
+        break;
+      case 'rotate':
+        setState(() {
+          _angle = _startAngle + dy * 0.9;
+        });
+        break;
+      case 'saturation':
+        setState(() {
+          _saturation = (_startSaturation + dy * 0.005).clamp(0.0, 2.0);
+        });
+        break;
+    }
+  }
+
+  void _onPointerUp(PointerUpEvent e) {
+    _interactionMode = 'none';
+  }
+
+  // ── Color filters ──
+
+  static const double _rLum = 0.2126;
+  static const double _gLum = 0.7152;
+  static const double _bLum = 0.0722;
+
+  ColorFilter _buildSaturationFilter() {
+    final s = _saturation;
+    final invS = 1.0 - s;
+    return ColorFilter.matrix(<double>[
+      invS * _rLum + s, invS * _gLum,     invS * _bLum,     0, 0,
+      invS * _rLum,     invS * _gLum + s, invS * _bLum,     0, 0,
+      invS * _rLum,     invS * _gLum,     invS * _bLum + s, 0, 0,
+      0,                0,                0,                1, 0,
+    ]);
+  }
+
+  ColorFilter _buildContrastFilter() {
+    final c = _contrast;
+    final t = (1.0 - c) / 2.0;
+    return ColorFilter.matrix(<double>[
+      c, 0, 0, 0, t,
+      0, c, 0, 0, t,
+      0, 0, c, 0, t,
+      0, 0, 0, 1, 0,
+    ]);
+  }
+
   Widget _buildImage() {
     return Image.file(
       key: _imageKey,
@@ -129,25 +279,42 @@ class _ImageCanvasState extends State<ImageCanvas> {
       builder: (context, constraints) {
         _vpSize = constraints.biggest;
         _clamp();
+
+        final vpCenterX = _vpSize.width / 2;
+        final vpCenterY = _vpSize.height / 2;
+        final angleRad = _angle * math.pi / 180;
+
         return SizedBox.expand(
           child: Stack(
             children: [
               ClipRect(
-                child: GestureDetector(
-                  onDoubleTap: _handleDoubleTap,
-                  onPanUpdate: _onPanUpdate,
-                  child: Listener(
-                    onPointerSignal: (event) {
-                      if (event is PointerScrollEvent) _handleScroll(event);
-                    },
+                child: Listener(
+                  onPointerDown: _onPointerDown,
+                  onPointerMove: _onPointerMove,
+                  onPointerUp: _onPointerUp,
+                  onPointerSignal: (event) {
+                    if (event is PointerScrollEvent) _handleScroll(event);
+                  },
+                  child: GestureDetector(
+                    onDoubleTap: _handleDoubleTap,
+                    onPanUpdate: _onPanUpdate,
                     child: Transform(
                       alignment: Alignment.topLeft,
                       transform: Matrix4.identity()
+                        ..translate(vpCenterX, vpCenterY)
+                        ..rotateZ(angleRad)
+                        ..translate(-vpCenterX, -vpCenterY)
                         ..translate(_tx, _ty)
                         ..scale(_sc),
-                      child: _isFilled
-                          ? SizedBox.expand(child: _buildImage())
-                          : Center(child: _buildImage()),
+                      child: ColorFiltered(
+                        colorFilter: _buildSaturationFilter(),
+                        child: ColorFiltered(
+                          colorFilter: _buildContrastFilter(),
+                          child: _isFilled
+                              ? SizedBox.expand(child: _buildImage())
+                              : Center(child: _buildImage()),
+                        ),
+                      ),
                     ),
                   ),
                 ),