docs: close §E approval-ergonomics re-audit (move to RETRO)

The re-audit passed and its one gap — line-only diff-viewer scroll — was
fixed in db27b34. Cut the BACKLOG §E item and record the result + the
diff-viewer paging commit in RETRO 2026-06-22.

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

BACKLOG.md

@@ -130,10 +130,6 @@ L0 injection, inline action rows, free-scroll/help/filter) is archived under RET
       spec this "lands with the planning pipeline" (a multi-candidate planner), which is unbuilt, so
       there is no wire shape to render against and nothing to unit-verify. Do NOT build a blind TUI
       view; revisit only once a `PlanCandidate`-bearing event exists. (Checked 2026-06-21.)
-- [ ] **§3 approval ergonomics re-audit** — the spec'd band (single-key y/n/e for T0–T2,
-      mandatory T3+ confirm, navigable queue, never modal-stacked) shipped `d5afcd3`. Re-verify
-      only because the band has since gained the grant scope-picker (`A`) and inline action rows —
-      a cheap live look, not a build.
 - ⏸ **§5.2 command-card LLM annotation layer** — deferred by spec ("ship layer 1, live with it,
       then decide whether layer 2 earns its place"). Build only after using layer 1.