feat(grips): add dynamic input and precision snapping

src/app/mod.rs

@@ -545,6 +545,13 @@ pub(super) struct OpenCADStudio {
     grip_originals: Vec<(acadrust::Handle, acadrust::EntityType)>,
     /// Document dirty state before the live grip mutation began.
     grip_dirty_before: Option<bool>,
+    /// Frozen wire geometry of the entities being grip-edited.
+    ///
+    /// The live entities are hidden from the resident hit-test set while their
+    /// grip preview is active. Keep their pre-drag geometry here so OSNAP,
+    /// Extension and OTRACK can still reference the entity's own vertices and
+    /// segments without snapping against the geometry being deformed.
+    grip_snap_wires: Vec<crate::scene::model::wire_model::WireModel>,
     /// Drag-start snapshot of the dragged entity's SDF glyph quads. A whole-
     /// entity text move slides these each frame (translating the already-shaped
     /// glyphs) instead of re-tessellating the run every cursor move (issue #316).
@@ -3109,6 +3116,7 @@ impl OpenCADStudio {
             hover_dwell: None,
             grip_originals: Vec::new(),
             grip_dirty_before: None,
+            grip_snap_wires: Vec::new(),
             grip_text_verts: Vec::new(),
             grip_text_slide: false,
             qselect: None,