Persist window positions when possible

src/config.rs

@@ -1,6 +1,6 @@
 use anyhow::Result;
 use clap::Parser;
-use egui::{Color32, Vec2};
+use egui::{Color32, Pos2, Vec2};
 use serde::{Deserialize, Serialize};
 
 use crate::{emulator::SimId, persistence::Persistence, window::DisplayMode};
@@ -75,6 +75,8 @@ pub struct SimConfig {
     pub dimensions: Vec2,
     #[serde(default = "default_audio_enabled")]
     pub audio_enabled: bool,
+    #[serde(default)]
+    pub position: Option<Pos2>,
 }
 
 impl SimConfig {
@@ -87,6 +89,7 @@ impl SimConfig {
             colors: COLOR_PRESETS[0],
             dimensions: DisplayMode::Anaglyph.proportions() + Vec2::new(0.0, 22.0),
             audio_enabled: true,
+            position: None,
         }
     }