Put text fill and the command-line preferences on the Display page

Three settings that work, persist, and could only be reached by typing their
name: TEXTFILL, CLIPROMPTLINES and COMMANDLINEFADETIME. The last two govern
how much of the command window is prompt and how long its history lingers —
the kind of thing people fiddle with once and then leave, which is exactly
what a settings dialog is for.

One fix rides along. TEXTFILL is a process-global, so changing it invalidates
the text in every open drawing; the SETVAR path rebuilt only the active tab,
leaving the others rendering the previous setting until an unrelated edit
happened to rebuild them. Both paths now go through
`invalidate_text_everywhere`, so the checkbox and the command cannot disagree.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/app/update/mod.rs

@@ -6200,6 +6200,29 @@ impl OpenCADStudio {
                 Task::none()
             }
 
+            Message::TextFillChanged(filled) => {
+                crate::scene::text::sdf_atlas::set_textfill(filled);
+                self.invalidate_text_everywhere();
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            Message::ClipromptLinesChanged(lines) => {
+                let lines = crate::app::settings::clamp_clipromptlines(lines);
+                self.cliprompt_lines = lines;
+                self.command_line.set_cliprompt_lines(lines.clamp(0, 50) as u8);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
+            Message::CommandLineFadeChanged(ms) => {
+                let ms = crate::app::settings::clamp_commandline_fade_ms(ms);
+                self.commandline_fade_ms = ms;
+                self.command_line.set_commandline_fade_ms(ms.max(0) as u32);
+                self.persist_settings_if_changed();
+                Task::none()
+            }
+
             Message::PickDragRectToggled(rectangle) => {
                 self.pick_drag_rect = rectangle;
                 self.persist_settings_if_changed();