3D resolution setting extended down to 1/16

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/settings.rs

@@ -142,7 +142,8 @@ pub struct Settings {
     pub wall_detail: u8, // 1 low, 2 medium, 3 high
     pub max_lights: u8,  // 8, 16 or 24
     pub ui_factor: u8,   // interface size: 0 = automatic, 1..4 = fixed integer factor
-    pub render_scale: u8, // 3D world resolution divisor: 1 = full, 2..4 = pixel look
+    pub render_scale: u8, // 3D world resolution divisor: 1 = full, 2..16 = pixel look
+    pub touch_ui: u8,     // touch interface: 0 = automatic (after the first touch), 1 = on, 2 = off
     // game
     pub game_speed: f32, // 1 or 2
     pub hints: bool,
@@ -168,6 +169,7 @@ impl Default for Settings {
             max_lights: 24,
             ui_factor: 0,
             render_scale: 1,
+            touch_ui: 0,
             game_speed: 1.0,
             hints: true,
             map_w: 64,