feat: window size presets — 4x8 screen-ratio grid in settings (v1.8.0)

- Settings 'Size' section: 8 col x 4 row grid, 31 buttons labeled a:b
  (a splits H, b splits W); top-left cell empty placeholder (no 1:1 —
  title bar double click already maximizes)
- Click resizes the window to work.width/b x work.height/a of the
  display's work area (screen_retriever visibleSize, taskbar excluded);
  position unchanged, no selection state tracking
- minimumSize 400x300 -> 160x100 (4:8 cell needs it)
- Settings file-properties rows left-aligned (were centered under path)

lib/widgets/window_size_selector.dart

@@ -0,0 +1,72 @@
+import 'package:flutter/material.dart';
+
+import '../l10n/app_localizations.dart';
+
+/// 8 sütun × 4 satır ekran oranı buton ızgarası.
+///
+/// Buton (sütun `b`, satır `a`) etiketi `"$a:$b"` → hedef boyut
+/// `W/b × H/a` (a dikeyi, b yatayı böler). Sol-üst hücre (1:1) boş
+/// placeholder — 1:1 yok (title bar çift tık zaten tam ekran).
+class WindowSizeSelector extends StatelessWidget {
+  final Future<Size?> Function() workArea;
+  final void Function(int rows, int cols, Size work) onPick;
+
+  const WindowSizeSelector({
+    super.key,
+    required this.workArea,
+    required this.onPick,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        Text(AppLocalizations.of(context)!.sizeSection,
+            style: const TextStyle(color: Colors.white70, fontSize: 13)),
+        const SizedBox(height: 4),
+        SingleChildScrollView(
+          scrollDirection: Axis.horizontal,
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              for (var a = 1; a <= 4; a++)
+                Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [
+                    for (var b = 1; b <= 8; b++)
+                      Padding(
+                        padding: const EdgeInsets.only(right: 4, bottom: 4),
+                        child: a == 1 && b == 1
+                            ? const SizedBox(width: 46, height: 26)
+                            : GestureDetector(
+                                onTap: () async {
+                                  final work = await workArea();
+                                  if (work != null) onPick(a, b, work);
+                                },
+                                child: Container(
+                                  width: 46,
+                                  height: 26,
+                                  decoration: BoxDecoration(
+                                    color: Colors.white10,
+                                    borderRadius: BorderRadius.circular(4),
+                                  ),
+                                  alignment: Alignment.center,
+                                  child: Text(
+                                    '$a:$b',
+                                    style: const TextStyle(
+                                        color: Colors.white, fontSize: 11),
+                                  ),
+                                ),
+                              ),
+                      ),
+                  ],
+                ),
+            ],
+          ),
+        ),
+      ],
+    );
+  }
+}