docs(backlog): mark brief echo-back gate shipped, add QA plan

BACKLOG.md

@@ -66,11 +66,15 @@ and §5 reviewer prompt/needs wiring (3467826) are shipped — RETRO candidates.
 
 ## C. Plan pipeline addenda — `docs/plans/2026-06-13-plan-pipeline-addenda.md`
 
-Entire spec is **unbuilt**.
+A1 is shipped (bcc59d2) — RETRO candidate once live-QA'd. A2/A3 remain.
 
-- [ ] **A1 brief echo-back gate** — planner restates brief as `BriefEcho`; harness diffs
-      referencedFiles/symbols/acceptanceCriteria vs original; divergence → `BriefEchoMismatchEvent`,
-      halt before any plan generation. (Cheapest failure point.)
+- [~] **A1 brief echo-back gate** — **SHIPPED (pending live-QA)** `bcc59d2`. New `brief_echo` stage
+      before the planner in `role_pipeline`: the model restates the analyst brief as a structured
+      artifact; a deterministic gate (`checkBriefEcho`, opt-in `brief_echo=true`) diffs the restatement
+      vs the brief — dropped requirements (Jaccard coverage < 0.34) or hallucinated files →
+      `BriefEchoMismatchEvent` + retryable stage failure, so a misread brief never reaches plan
+      generation. Pure replay-safe diff (`BriefEchoDiff`); symbols recorded but non-blocking in v1.
+      QA gate in §F → `docs/qa/QA-brief-echo-gate.md`. `freestyle_planning` wiring is a follow-up.
 - [ ] **A2 stage-level plan checkpointing** — reconciliation compares produced artifacts vs
       the confirmed plan's produces-slots per stage; `StageCheckpointPassedEvent` /
       `StageCheckpointFailedEvent` (halt + surface).
@@ -135,6 +139,10 @@ These are SHIPPED in code but prompt-/server-/network-dependent and not yet live
       (responsive→HEALTHY, no-log-pollution, slow/throw→DEGRADED, restore hysteresis, replay independence).
 - [ ] **Health TUI pane live-QA** — `fd67a6c`. Plan: `docs/qa/QA-health-tui-pane.md` (`H` opens/fetches,
       matches `correx health`, degraded loud, disabled fallback, resize, live wire-contract values).
+- [ ] **Brief echo-back gate live-QA** — `bcc59d2`; needs a real planner-capable model + runtime install
+      (schema/prompt/artifacts block). Plan: `docs/qa/QA-brief-echo-gate.md` (faithful echo→planner runs,
+      dropped requirement→`BriefEchoMismatchEvent`+retryable fail, hallucinated file flagged, symbols
+      non-blocking, replay recomputes identically, non-opted pipeline is a no-op).
 - [ ] **TUI kernel-steering + AMD gauge fresh live-QA** — approve+note actually revising the
       *same* stage's output; AMD VRAM/RAM gauge on the real box.
 - [ ] **Unit-tested-only fixes, not live-verified:** `1a7eb05` (verdict-edge rejection),