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 <[email protected]>

src/app/view/modal.rs

@@ -195,6 +195,9 @@ impl OpenCADStudio {
                         crate::ui::window::options::AppPrefs {
                             savetime_min: self.savetime_min,
                             backup_on_save: self.backup_on_save,
+                            textfill: crate::scene::text::sdf_atlas::textfill(),
+                            cliprompt_lines: self.cliprompt_lines,
+                            commandline_fade_ms: self.commandline_fade_ms,
                         },
                         self.double_click_block_refedit,
                         self.double_click_block_attedit,