Simplify: extract paint_glyph, drop unused param and redundant comments

- Add paint_glyph(painter, rect, glyph) to render.rs; draw_glyph now
  delegates to it, eliminating the duplicated rect_filled+text pattern
  that appeared in four places across editor.rs and glyph_picker.rs
- Remove unused _board param from show_editor_panel and its call site
- Drop redundant section-header comments in glyph_picker.rs (the
  ui.label() calls immediately below already name each section)
- Remove extracted fg/bg/cur_ch locals in the char grid loop now that
  paint_glyph accepts a Glyph directly
- Fix CLAUDE.md update phase description (stale from pre-refactor)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/editor.rs

@@ -1,8 +1,8 @@
 use eframe::egui;
-use egui::{Align2, FontId, Sense, vec2};
+use egui::{Sense, vec2};
 
-use crate::game::{Archetype, Board, Glyph, ALL_ARCHETYPES};
-use crate::render::{CELL_H, CELL_W, PALETTE_PANEL_W};
+use crate::game::{Archetype, Glyph, ALL_ARCHETYPES};
+use crate::render::{CELL_H, CELL_W, PALETTE_PANEL_W, paint_glyph};
 
 /// Which tab is active in the editor side panel.
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -43,12 +43,11 @@ impl EditorState {
 ///
 /// Shows tab bar (Palette / Board / World) and, on the Palette tab, the
 /// scrollable archetype list and current-glyph preview button.
-pub(crate) fn show_editor_panel(ctx: &egui::Context, editor: &mut EditorState, _board: &Board) {
+pub(crate) fn show_editor_panel(ctx: &egui::Context, editor: &mut EditorState) {
     egui::SidePanel::right("palette_panel")
         .resizable(true)
         .default_width(PALETTE_PANEL_W)
         .show(ctx, |ui| {
-            // Tab bar
             ui.horizontal(|ui| {
                 ui.selectable_value(&mut editor.tab, EditorTab::Palette, "Palette");
                 ui.selectable_value(&mut editor.tab, EditorTab::Board,   "Board");
@@ -72,12 +71,7 @@ pub(crate) fn show_editor_panel(ctx: &egui::Context, editor: &mut EditorState, _
                                 ui.horizontal(|ui| {
                                     let (r, cell_resp) = ui.allocate_exact_size(
                                         vec2(CELL_W, CELL_H), Sense::click());
-                                    {
-                                        let p = ui.painter();
-                                        p.rect_filled(r, 0.0, glyph.bg);
-                                        p.text(r.center(), Align2::CENTER_CENTER,
-                                            glyph.ch, FontId::monospace(CELL_H), glyph.fg);
-                                    }
+                                    paint_glyph(ui.painter(), r, &glyph);
                                     let label_resp =
                                         ui.selectable_label(is_selected, archetype.name());
                                     if cell_resp.clicked() || label_resp.clicked() {
@@ -94,17 +88,7 @@ pub(crate) fn show_editor_panel(ctx: &egui::Context, editor: &mut EditorState, _
                     // Paint a preview cell showing the current glyph, sized like a board cell.
                     let (cell_rect, glyph_btn) =
                         ui.allocate_exact_size(vec2(CELL_W, CELL_H), Sense::click());
-                    {
-                        let p = ui.painter();
-                        p.rect_filled(cell_rect, 0.0, editor.glyph.bg);
-                        p.text(
-                            cell_rect.center(),
-                            Align2::CENTER_CENTER,
-                            editor.glyph.ch,
-                            FontId::monospace(CELL_H),
-                            editor.glyph.fg,
-                        );
-                    }
+                    paint_glyph(ui.painter(), cell_rect, &editor.glyph);
                     if glyph_btn.clicked() {
                         editor.glyph_picker_open = true;
                     }