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

docs/index.md

@@ -0,0 +1,6 @@
+# imajViewer — Dokümantasyon İndeksi
+
+| Tarih | Dosya | Konu |
+|---|---|---|
+| 2026-07-27 | [image-canvas-interactions.md](image-canvas-interactions.md) | Sağ tık etkileşimleri: contrast, saturation, rotate |
+| önceki | [zoom-clamp-mekanizmasi.md](zoom-clamp-mekanizmasi.md) | Zoom clamp mekanizması (letterbox-aware) |