docs(backlog): scope item 33 (rofi scrollbar) as a ~10-file visual slice

Found every authored .rasi deliberately hides the scrollbar (width:0), so
the overflow hint needs per-theme tuning across ~10 files with a V3-only
payoff — recorded so it is picked up in a themed session, not blind.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/BACKLOG.md

@@ -248,6 +248,14 @@ onto another page, nothing signals there's more below. Add a scrollbar
 (rofi's `scrollbar` element) or a "more ↓" hint, themed to the palette,
 on the launcher grid and the long text menus. Check rofi 2.0.0's
 scrollbar support/theming.
+_Scoped 2026-07-07:_ rofi only draws the scrollbar when the list actually
+overflows (`lines < rows`), so enabling it self-hides on short menus —
+the right primitive. But it's a **visual, ~10-file slice**: the generated
+palette theme (`rofi.nix`, `scrollbar = false`) **plus every authored
+`.rasi`** (boreal/nord/lumon/kanagawa/retro-82/neon-glass/executive-slate/
+summer-day/summer-night) — all deliberately set `scrollbar { width:0 }`
+today, each needs a per-theme handle width/colour. Payoff is V3-only
+(rendering), so it wants a themed session, not a headless edit.
 
 ### 35. Right-click volume → audio control app
 (Raised by Bernardo, 2026-07-07 — item 5.) Right-click the Waybar

flake.lock

@@ -166,11 +166,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1782562157,
+        "lastModified": 1783370751,
-        "narHash": "sha256-a7+T6QSeowynwZ1ZJJbP8T8ntAytvrui8kFGJmIZt2c=",
+        "narHash": "sha256-E+3MIMvKuo9k+K+qLQ9YXzsBzkgHuyVLnsEbN2DFfuc=",
         "owner": "NixOS",
         "repo": "nixos-hardware",
-        "rev": "a9cf7546a938c737b079e738de73934a13de9784",
+        "rev": "662bd6e312d2c8b212e32cb377abaee190749320",
         "type": "github"
       },
       "original": {
@@ -249,11 +249,11 @@
         "tinted-zed": "tinted-zed"
       },
       "locked": {
-        "lastModified": 1783308448,
+        "lastModified": 1783359251,
-        "narHash": "sha256-n+OcIYCfHofQgsuDJ5w42BNoGDnJwmd7tHqLNpVaJOU=",
+        "narHash": "sha256-HUiCnEVlJ4n+qJlZojiz/zv+P0cqM5zsg1dxpz2J7Mg=",
         "owner": "nix-community",
         "repo": "stylix",
-        "rev": "a5b35360dd2f9a931e85457c3d6d9688307b939f",
+        "rev": "e602ad042f00409f33c8ad2829cd8d59ba345c7e",
         "type": "github"
       },
       "original": {