Feat: PEDIT command (PE) — polyline edit (close/open/width)

Entity pick → text input subcommands:
  C / CLOSE  → set closed flag
  O / OPEN   → clear closed flag
  W <value>  → set uniform width on LwPolyline vertices
  X / EXIT   → cancel

Command stays active after each op (CmdResult::PeditOp) for multiple edits.
Supports LwPolyline and Polyline2D.

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/command/mod.rs

@@ -99,6 +99,11 @@ pub enum CmdResult {
     BreakEntity { handle: Handle, p1: Vec3, p2: Vec3 },
     /// Attempt to join the given entities into fewer merged entities.
     JoinEntities(Vec<Handle>),
+    /// Apply a polyline-edit operation to one entity; keep command active.
+    PeditOp {
+        handle: Handle,
+        op: crate::modules::home::modify::pedit::PeditOp,
+    },
     /// Place Point entities at N equal intervals along the entity.
     DivideEntity { handle: Handle, n: usize },
     /// Place Point entities at `segment_length` intervals along the entity.