docs(agent): icon-weight A/B captured + published for the item-28 human call

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

agent/BACKLOG.md

@@ -76,6 +76,14 @@ review:
   - **Icon weight mix `[human]`:** full-color Papirus icons in the
     menus vs all-monochrome bar glyphs — pick: symbolic/monochrome
     menu icons for one system, or color as the menu's identity.
+    A/B captured on lumon (iteration #46, side-by-side:
+    https://claude.ai/code/artifact/1ccd10fe-4b6f-454a-888d-e7fdf2362b03):
+    B (symbolic) matches the bar's weight but Papirus symbolic
+    coverage has holes (preferences-desktop-theme-symbolic missing —
+    Look & Feel lost its icon) and rofi tints symbolics a fixed dim
+    gray, not the theme text color — going B needs an icon audit +
+    recolor slice. A costs nothing. Awaiting the call; A stays until
+    then.
   - ✓ **Bar right-cluster rhythm** (shipped iteration #36): group
     margins before pulseaudio/powerprofile/battery — heads that
     self-hide degrade to the uniform spacing.