chore: remove dead UI helpers and orphan toolbar stubs

Each item below was gated by #[allow(dead_code)] and has zero callers
across src/ — none of them are part of any public API consumed by
external crates (this is a binary, not a library):

* modules/insert/underlay_frames.rs + edit_aliases.rs — toolbar stubs
  whose `tool()` registrars were never wired into the ribbon; the
  parent mod.rs inlines its own include_bytes! for the SVGs, so the
  files were orphan dead weight.
* ui/snap_popup.rs:snap_marker_color — never called.
* ui/ribbon/mod.rs:last_dropdown_cmd — never called.
* ui/scale_popup.rs:anno_scale_for_label — never called.
* ui/layers.rs:color_name_to_aci — inverse of aci_color_display
  with zero call sites.
* linetypes.rs:name_list — never called.
* scene/pipeline/wire_gpu.rs:new_ghost — never called.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/modules/insert/mod.rs

@@ -16,7 +16,6 @@ mod open_obj;
 mod pc_attach;
 mod snap_underlays;
 pub(crate) mod solid3d_cmds;
-mod underlay_frames;
 mod underlay_layers;
 pub(crate) mod wblock;
 mod xadjust;

src/modules/insert/underlay_frames.rs

@@ -1,13 +0,0 @@
-use crate::modules::{IconKind, ModuleEvent, ToolDef};
-#[allow(dead_code)]
-pub const ICON: IconKind =
-    IconKind::Svg(include_bytes!("../../../assets/icons/underlay_frames.svg"));
-#[allow(dead_code)]
-pub fn tool() -> ToolDef {
-    ToolDef {
-        id: "FRAMES",
-        label: "Frames",
-        icon: ICON,
-        event: ModuleEvent::Command("FRAMES".to_string()),
-    }
-}