feat: persist panel widths, enforce line limits, and improve font selection

Implemented four efficiency and usability improvements from the TODO list:

- Added Persistent Panel Widths: Debug, History, Settings, and Theme Editor panels now save and restore their user-adjusted widths.
- Improved History Capacity: Increased default limit to 1000 items. Modified logic so global limit changes only affect newly created files.
- Enforced Line Limit: Introduced a configurable line limit (default 1000) that truncates content and warns the user when exceeded. Can be disabled by setting it to 0.
- Enhanced Font Selection: Added support for confirming font choices with the "Enter" key in both UI and Editor font dropdowns.
- Refactored Editor Logic: Restructured the text editor's rendering loop to resolve borrow-checker issues and improve code maintainability.

Author: Avaray

src/app.rs

@@ -587,43 +587,67 @@ impl eframe::App for EditorApp {
 
         // Theme Editor panel (right)
         if self.show_theme_editor {
-            egui::SidePanel::right("theme_editor")
+            let panel_res = egui::SidePanel::right("theme_editor")
                 .resizable(true)
-                .default_width(270.0)
+                .default_width(self.settings.theme_editor_width)
                 .show(ctx, |ui| {
                     self.render_theme_editor_panel(ui);
                 });
+                
+            let actual_width = panel_res.response.rect.width();
+            if (actual_width - self.settings.theme_editor_width).abs() > 1.0 {
+                self.settings.theme_editor_width = actual_width;
+                let _ = self.settings.save();
+            }
         }
 
         // Settings panel (right)
         if self.show_settings_panel {
-            egui::SidePanel::right("settings_panel")
+            let panel_res = egui::SidePanel::right("settings_panel")
                 .resizable(true)
-                .default_width(350.0)
+                .default_width(self.settings.settings_panel_width)
                 .min_width(300.0)
                 .show(ctx, |ui| {
                     self.render_settings_panel(ui);
                 });
+                
+            let actual_width = panel_res.response.rect.width();
+            if (actual_width - self.settings.settings_panel_width).abs() > 1.0 {
+                self.settings.settings_panel_width = actual_width;
+                let _ = self.settings.save();
+            }
         }
 
         // History panel (right)
         if self.show_history_panel {
-            egui::SidePanel::right("history")
+            let panel_res = egui::SidePanel::right("history")
                 .resizable(true)
-                .default_width(250.0)
+                .default_width(self.settings.history_panel_width)
                 .show(ctx, |ui| {
                     self.render_history_panel(ui);
                 });
+                
+            let actual_width = panel_res.response.rect.width();
+            if (actual_width - self.settings.history_panel_width).abs() > 1.0 {
+                self.settings.history_panel_width = actual_width;
+                let _ = self.settings.save();
+            }
         }
 
         // Debug panel (right, below history if both shown)
         if self.show_debug_panel {
-            egui::SidePanel::right("debug")
+            let panel_res = egui::SidePanel::right("debug")
                 .resizable(true)
-                .default_width(250.0)
+                .default_width(self.settings.debug_panel_width)
                 .show(ctx, |ui| {
                     self.render_debug_panel(ui);
                 });
+                
+            let actual_width = panel_res.response.rect.width();
+            if (actual_width - self.settings.debug_panel_width).abs() > 1.0 {
+                self.settings.debug_panel_width = actual_width;
+                let _ = self.settings.save();
+            }
         }
 
         // Central editor

src/history.rs

@@ -48,15 +48,15 @@ pub struct DocumentWithHistory {
 }
 
 fn default_max_history() -> usize {
-    100
+    1000
 }
 
 impl Default for DocumentWithHistory {
     fn default() -> Self {
         Self {
             current_content: String::new(),
             history: Vec::new(),
-            max_history_length: 100,
+            max_history_length: 1000,
         }
     }
 }
@@ -98,15 +98,15 @@ impl DocumentWithHistory {
                 Self {
                     current_content,
                     history,
-                    max_history_length: 100,
+                    max_history_length: 1000,
                 }
             }
         } else {
             // No history, just content
             Self {
                 current_content: file_content.to_string(),
                 history: Vec::new(),
-                max_history_length: 100,
+                max_history_length: 1000,
             }
         }
     }

src/settings.rs

@@ -80,10 +80,32 @@ pub struct Settings {
     pub show_debug_panel: bool,
     /// File tree panel width
     pub file_tree_width: f32,
+    
+    /// Theme editor panel width
+    #[serde(default = "default_panel_width_270")]
+    pub theme_editor_width: f32,
+    
+    /// Settings panel width
+    #[serde(default = "default_panel_width_350")]
+    pub settings_panel_width: f32,
+    
+    /// History panel width
+    #[serde(default = "default_panel_width_250")]
+    pub history_panel_width: f32,
+    
+    /// Debug panel width
+    #[serde(default = "default_panel_width_250")]
+    pub debug_panel_width: f32,
+
     /// Show subfolders in file tree
     pub show_subfolders: bool,
+    
     /// Max history length
     pub max_history_length: usize,
+    
+    /// Editor line limit (0 means disabled)
+    #[serde(default = "default_max_lines")]
+    pub max_lines: usize,
 
     /// Whether to show full keyfile path in status bar
     #[serde(default)]
@@ -133,6 +155,22 @@ fn default_toolbar_icon_size() -> f32 {
     24.0
 }
 
+fn default_panel_width_250() -> f32 {
+    250.0
+}
+
+fn default_panel_width_270() -> f32 {
+    270.0
+}
+
+fn default_panel_width_350() -> f32 {
+    350.0
+}
+
+fn default_max_lines() -> usize {
+    1000
+}
+
 impl Default for Settings {
     fn default() -> Self {
         Self {
@@ -158,8 +196,13 @@ impl Default for Settings {
 
             show_debug_panel: false,
             file_tree_width: 200.0,
+            theme_editor_width: default_panel_width_270(),
+            settings_panel_width: default_panel_width_350(),
+            history_panel_width: default_panel_width_250(),
+            debug_panel_width: default_panel_width_250(),
             show_subfolders: true,
             max_history_length: 100,
+            max_lines: default_max_lines(),
 
             show_keyfile_path: false,
             start_maximized: false,