File-association list view in settings + fix ghost glyphs after window moves

- New 'Filformat' row in the settings dialog opens a list of all
  [open_with] associations (.ext → command) plus the default editor;
  Delete removes an association (persisted to config.toml), Esc goes
  back
- Ghost fix: some terminals leave the right half of wide glyphs
  (emoji) behind when the diff only rewrites part of them — windows
  being dragged/resized/closed/snapped now request one full terminal
  repaint on completion, clearing any leftovers. Verified the
  compositor itself is clean (headless frames have no ghosts)
- Integration suite: 41/41

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

src/main.rs

@@ -262,6 +262,12 @@ fn run_standalone_loop(
         // ── Kitty bakgrundsbild ──────────────────────────────────────────
         update_background(terminal, app, &mut bg_state, size.width, size.height);
 
+        // Full omritning efter fönsterflytt/-stängning: rensar halva
+        // emoji-glyfer ("spöken") som terminal-diffen annars lämnar kvar.
+        if app.needs_full_redraw {
+            app.needs_full_redraw = false;
+            terminal.clear()?;
+        }
         terminal.draw(|frame| {
             let area = frame.area();
             app.update_layout(area);