fix(rofi): drop the go-previous icon from menu Back rows

Every submenu's "↩ Back" row rendered two arrows: the ↩ glyph in the
label plus a themed go-previous icon. back() now emits the plain label
only — identical to what pick-lists already append — so Back shows a
single glyph everywhere. BACK="↩ Back" stays the universal label/match,
so no case-branch comparison changes.

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

modules/home/rofi.nix

@@ -188,12 +188,14 @@ let
     # Esc is their back path; free-text prompts (web, ask) have no list to
     # append to — Esc cancels. Everything hand-rolled gets the row below.
     # General menu convention: every list menu ends with a "↩ Back" entry that
-    # returns one level up (so you never have to Esc out and reopen). `back`
-    # emits it with an icon; plain pick-lists append the bare label instead.
-    # Always matched EXACTLY ("↩ Back") so it can't collide with clipboard or
-    # filename content. The arrow + go-previous icon read as "go back".
+    # returns one level up (so you never have to Esc out and reopen). The `↩`
+    # glyph in the label IS the arrow — `back` must not also attach a
+    # go-previous icon, or icon menus render two arrows (item 34). So `back`
+    # is now just the plain-label emit, identical to what pick-lists append —
+    # one arrow everywhere. Always matched EXACTLY ("↩ Back") so it can't
+    # collide with clipboard or filename content.
     BACK="↩ Back"
-    back() { row "$BACK" go-previous; }
+    back() { printf '%s\n' "$BACK"; }
 
     case "''${1:-}" in
       power)