docs: create RETRO.md, flatten BACKLOG to unbuilt-work-only

RETRO.md never existed, so every shipped/pending-QA item piled up in BACKLOG. Create it
(Pending live-QA + Landed sections) and move all shipped code there. Rewrite BACKLOG flat,
grouped by actionability (active epic / ready / blocked / won't-build) instead of by spec,
one line per item.

RETRO.md

@@ -0,0 +1,57 @@
+# CORREX — RETRO (archive of what got done)
+
+> Counterpart to `BACKLOG.md` (live unbuilt work only). Two states here:
+> **Pending live-QA** = shipped in code, awaiting live verification (has a `docs/qa/QA-*.md` plan or a
+> stated gate). **Landed** = built and verified, or no QA gate needed.
+> **Flow:** ship a feature → move it straight here under *Pending live-QA* (do NOT leave it in BACKLOG) →
+> when its QA plan passes, move it down to *Landed* with the run date. On QA FAIL, refile the misses into
+> BACKLOG as numbered findings.
+
+---
+
+## Pending live-QA
+
+Shipped in code, prompt-/server-/network-dependent, not yet live-verified. Each names commit(s) + the
+evidence to check.
+
+- **§4 health-checks (3 probes + TUI pane — retire as one unit)** — llama-server probe `aaf896d`
+  (`docs/qa/QA-llama-health-probe.md`), event-store probe `7a1362c`
+  (`docs/qa/QA-event-store-health-probe.md`), live health TUI pane `fd67a6c` over the backbone `f8fd260`
+  (`docs/qa/QA-health-tui-pane.md`). Needs a real llama-server + server up.
+- **Static-first reviewer gate** — `365eb8a` (prompt half `3467826`). `docs/qa/QA-static-first-reviewer.md`:
+  clean→reviewer runs, non-clean→`StaticAnalysisCompleted`+retryable fail w/ output fed back, gate-OFF
+  absence, no-runner WARN, replay reads recorded findings. Needs an implementer-capable model + a workspace
+  whose `static_analysis` commands can be made to pass/fail.
+- **Brief echo-back gate** — `bcc59d2`. `docs/qa/QA-brief-echo-gate.md`: faithful echo→planner runs,
+  dropped requirement→`BriefEchoMismatchEvent`+retryable fail, hallucinated file flagged, symbols
+  non-blocking, replay stable, non-opted pipeline is a no-op. Needs a planner-capable model + runtime
+  install (schema/prompt/artifacts block).
+- **Plan-lint (plan-pipeline §5, Slice 1)** — `68136e7`. `docs/qa/QA-plan-lint.md`: unproduced_need /
+  trap_state → `PlanLintCompleted` + `ExecutionPlanRejected(source=lint)` + no lock; review-loop NOT
+  trapped; soft findings non-blocking; replay stable. Logic is unit-covered → confirmatory pass.
+- **Epic 15 — observability/replay tooling** — `a7d5211..75703ec`. Gate: server up → `correx events` /
+  `correx replay` on a real session, confirm MDC sessionIds in logs.
+- **Research workflow (core, ON by default)** — `fb1d970..378ee39`. Needs SearXNG + network: exercise
+  triage→fetch-approval→report→artifact viewer. (Unbuilt follow-ups stay in BACKLOG.)
+- **Idea board** — `3ac0a14..02e963d`. Needs a real router model to emit the `{"ideas":[…]}` block.
+- **Clarification loop + workflow-propose panel** — prompt-dependent (need a real router/analyst model to
+  emit the structured JSON blocks). `clarcard.go` / `proposecard.go`.
+- **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), `e195c79`
+  (stale-parking `OrchestrationPaused ABANDONED_STALE`), `df3ee0b` (bare-id narration model match).
+
+## Landed (built & verified, or no QA gate)
+
+- **Freestyle mode epic** — `63e5bce..4d1b4ff`. Two-phase planning→execution; **live-QA gate B4 PASSED**
+  2026-06-12. (Deferred follow-ups live in BACKLOG.)
+- **Router triage + repo-knowledge epic** — `ac458d8..1976d8a`. **Live QA PASSED 2026-06-11** (all 7
+  checks after fixes `07819ec`/`50602b0`).
+- **Single-project consistency epic** — `fba2bbb..ed0dca8`. T1–T10 (phantom fix, plan-rejected event+gate,
+  ProjectProfile L0, retry/critic feedback, architect vocabulary).
+- **Observability §3 — metrics + `correx stats` + TUI stats pane** — `fe94140`, `4f6bfa8`.
+- **Role-reliability shipped halves** — §3 analyst keystone `894969d`, §3 entity grounding (`ground_references`
+  → `BriefGroundingCheckedEvent`, FS probe) `b050dc4`, §2 write-manifest (`ManifestContainmentRule`)
+  `4e5e4e5`, §5 reviewer narrow-question prompt/needs `3467826`.
+- **TUI requirements shipped halves** — §2 last-event clock + unknown-event fallback `8b896b5`, §5.1
+  deterministic command-approval parse card `65df3f4`.