fix(osnap): a POINT snaps as a Node only

A point carried a key vertex, so Endpoint (which outranks Node) claimed
it, and an absolute-size glyph's strokes were indexed for Nearest and
Intersection. Points now offer only their Node, in the indexed and the
unindexed snap paths alike.

Fixes #1570

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/scene/model/wire_model.rs

@@ -744,6 +744,11 @@ impl WireModel {
     pub fn is_display_only(&self) -> bool {
         self.snap_only && self.display_visible
     }
+    /// A POINT's wire: the Node is its only snap; the glyph strokes are drawn
+    /// but offer no endpoints or segments to snap to.
+    pub fn is_node_marker(&self) -> bool {
+        self.key_vertices.is_empty() && matches!(self.snap_pts.as_slice(), [(_, SnapHint::Node)])
+    }
     /// Sentinel AABB that never rejects any snap query.
     pub const UNBOUNDED_AABB: [f32; 4] = [
         f32::NEG_INFINITY,