fix(text): show text in command previews (move/copy/etc) (#316)

Command previews (MOVE, COPY, ROTATE, SCALE, STRETCH, MIRROR, ARRAY,
PASTE, INSERT) build ghost WireModels via WireModel::translated/rotated/
scaled/stretched/mirrored, but those helpers moved only `points`, never
`text_verts`, and the ghosts' glyphs were never uploaded — so text
vanished (or froze at its source) during the preview, same root cause as
the grip-drag case.

Transform text_verts alongside points in all five helpers (shared
map_text_verts, reconstructing + re-splitting the double-single world
position), and gather preview_wires' glyphs into the per-frame
preview-text buffer in the render path. This covers every command
preview automatically. The grip-drag else branch no longer sets
preview_text explicitly (the render gather handles it); the grip-slide
fast path keeps its own scene.preview_text channel (empty preview_wires,
so no double-draw).

MIRROR honours MIRRTEXT: on -> true glyph mirror via mirrored(); off ->
readable relocation via translated().

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/app/update/viewport.rs

@@ -812,12 +812,11 @@ pub(super) fn on_tick(&mut self, t: Instant) -> Task<Message> {
                         self.tabs[i].scene.set_preview_text(slid);
                         self.tabs[i].scene.set_preview_wires(Vec::new());
                     } else {
+                        // Wire geometry, or a reshape grip: re-tessellate. The
+                        // preview WireModels carry the entity's glyphs (gathered
+                        // for the preview-text buffer in the render path), so a
+                        // dimension / MTEXT-width drag keeps its text visible too.
                         let preview = self.tabs[i].scene.wire_models_for(&[grip.handle]);
-                        let ptext = preview
-                            .iter()
-                            .flat_map(|w| w.text_verts.iter().copied())
-                            .collect();
-                        self.tabs[i].scene.set_preview_text(ptext);
                         self.tabs[i].scene.set_preview_wires(preview);
                     }
                     self.refresh_selected_grips();