fix(start): complete Start page workflow

Track Save As paths, persist the selected section, and size tabbed
panels from their actual available width.

Refs #443

src/app/config.rs

@@ -20,6 +20,8 @@ pub struct AppConfig {
     pub settings: UserSettings,
     /// Recent-files list + retained count.
     pub recent: RecentConfig,
+    /// Last selected section on the tabbed Start page.
+    pub start: StartConfig,
     /// Which status-bar pills the user has hidden.
     pub statusbar: StatusBarConfig,
     /// Ribbon collapse density.
@@ -34,6 +36,7 @@ impl Default for AppConfig {
         Self {
             settings: UserSettings::default(),
             recent: RecentConfig::default(),
+            start: StartConfig::default(),
             statusbar: StatusBarConfig::default(),
             ribbon: RibbonConfig::default(),
             plot: PlotDialogState::default(),
@@ -59,6 +62,12 @@ impl Default for RecentConfig {
     }
 }
 
+#[derive(Clone, PartialEq, Serialize, Deserialize, Default)]
+#[serde(default)]
+pub struct StartConfig {
+    pub section: super::StartSection,
+}
+
 #[derive(Clone, PartialEq, Serialize, Deserialize, Default)]
 #[serde(default)]
 pub struct RibbonConfig {

src/app/mod.rs

@@ -211,7 +211,9 @@ struct AddSelectedRestore {
 }
 
 /// Which Start-page section a narrow (tabbed) Start page is showing.
-#[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
+#[derive(
+    Clone, Copy, PartialEq, Eq, Default, Debug, serde::Serialize, serde::Deserialize,
+)]
 pub enum StartSection {
     Recent,
     Videos,

src/app/update/file.rs

@@ -292,6 +292,9 @@ impl OpenCADStudio {
                     .collect(),
                 limit: self.recent_limit,
             },
+            start: crate::app::config::StartConfig {
+                section: self.start_section,
+            },
             statusbar: self.statusbar_config.clone(),
             ribbon: crate::app::config::RibbonConfig {
                 collapse: self.ribbon.collapse_mode(),
@@ -317,6 +320,7 @@ impl OpenCADStudio {
         self.recent_limit_input = self.recent_limit.to_string();
         // Thumbnails are decoded by a background task queued at boot
         // (`refresh_recent_thumbs`) — never here on the boot path.
+        self.start_section = cfg.start.section;
         self.statusbar_config = cfg.statusbar;
         self.ribbon.set_collapse_mode(cfg.ribbon.collapse);
         self.plot_dialog = cfg.plot;
@@ -952,9 +956,14 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
                 self.tabs[i].current_path = Some(path.clone());
                 self.tabs[i].dirty = false;
                 let _ = std::fs::remove_file(path.with_extension("sv$"));
+                let recent = self.push_recent(path.clone());
                 if self.save_dialog_for_unsaved {
-                    return self.update(Message::UnsavedPickedSavePath(Some(path)));
+                    return Task::batch([
+                        recent,
+                        self.update(Message::UnsavedPickedSavePath(Some(path))),
+                    ]);
                 }
+                return recent;
             }
             Err(e) => self.command_line.push_error(&format!("Save failed: {e}")),
         }

src/app/update/mod.rs

@@ -224,6 +224,7 @@ impl OpenCADStudio {
 
             Message::StartSectionSelect(section) => {
                 self.start_section = section;
+                self.save_config();
                 Task::none()
             }
 

src/app/view/mod.rs

@@ -115,18 +115,21 @@ impl OpenCADStudio {
         // viewport draws the layout's own geometry (white sheet + entities +
         // borders) and the floating content viewports blit on top.
         let viewport_3d: Element<'_, Message> = if tab.is_start {
-            start_page_view(
-                &self.patrons,
-                &self.videos,
-                self.videos_loading,
-                &self.video_thumbs,
-                &self.recent_files,
-                &self.recent_thumbs,
-                self.recent_limit,
-                &self.recent_limit_input,
-                self.win_size.0,
-                self.start_section,
-            )
+            responsive(|size| {
+                start_page_view(
+                    &self.patrons,
+                    &self.videos,
+                    self.videos_loading,
+                    &self.video_thumbs,
+                    &self.recent_files,
+                    &self.recent_thumbs,
+                    self.recent_limit,
+                    &self.recent_limit_input,
+                    size.width,
+                    self.start_section,
+                )
+            })
+            .into()
         } else if is_paper {
             shader(ViewportPane::model(
                 &tab.scene,
@@ -2504,7 +2507,17 @@ pub(super) fn start_page_view<'a>(
     let fits_all = avail
         >= recent_w + sup_w + 2.0 * 16.0 + welcome_min + 2.0 * (videos_w + 16.0);
 
-    let recent = recent_files_panel(recents, thumbs, recent_limit, recent_limit_input);
+    let recent = recent_files_panel(
+        recents,
+        thumbs,
+        recent_limit,
+        recent_limit_input,
+        if fits_all {
+            iced::Length::Fixed(recent_w)
+        } else {
+            iced::Length::Fill
+        },
+    );
     let welcome = container(content).width(Fill).height(Fill);
 
     // Tutorial-videos rail: the official playlist, fetched at boot (cached on
@@ -2593,7 +2606,11 @@ pub(super) fn start_page_view<'a>(
             Space::new().height(iced::Length::Fixed(12.0)),
             playlist_btn,
         ])
-        .width(iced::Length::Fixed(videos_w))
+        .width(if fits_all {
+            iced::Length::Fixed(videos_w)
+        } else {
+            iced::Length::Fill
+        })
         .height(Fill)
         .padding(16)
         .style(|_: &Theme| container::Style {
@@ -2672,7 +2689,11 @@ pub(super) fn start_page_view<'a>(
             Space::new().height(iced::Length::Fixed(12.0)),
             support_btn,
         ])
-        .width(iced::Length::Fixed(240.0))
+        .width(if fits_all {
+            iced::Length::Fixed(sup_w)
+        } else {
+            iced::Length::Fill
+        })
         .height(Fill)
         .padding(20)
         .style(|_: &Theme| container::Style {
@@ -2804,6 +2825,7 @@ pub(super) fn recent_files_panel<'a>(
     >,
     limit: usize,
     limit_input: &'a str,
+    width: iced::Length,
 ) -> Element<'a, Message> {
     // Card chrome matches the Supporters rail (the canonical start-page card).
     const PANEL_BG: Color = Color {
@@ -2993,7 +3015,7 @@ pub(super) fn recent_files_panel<'a>(
         ]
         .width(Fill),
     )
-    .width(iced::Length::Fixed(280.0))
+    .width(width)
     .height(Fill)
     .padding(20)
     .style(|_: &Theme| container::Style {
@@ -3007,4 +3029,3 @@ pub(super) fn recent_files_panel<'a>(
     })
     .into()
 }
-