docs(overhaul): stop S4-c2 after final review

docs/research/2026-09-01-overhaul/2026-09-04-s4-handoff.md

@@ -1,9 +1,11 @@
-# Campaign OVERHAUL v2 — hand-off at S4 chunk 2, fix round 1 DONE / round review NOT started (2026-09-04 ~12:20 local)
+# Campaign OVERHAUL v2 — hand-off at S4 chunk 2 STOPPED UNLANDED after the final allowed round (2026-09-04)
 
-Clean state for a fresh session. Everything referenced is on disk under the
-Windows user `erikn`; a different Claude account on this machine reads it all.
-No subagent is running at hand-over: the chunk-2 fixer finished and committed
-(`cc8e5677a` in worktree `s4-c2-impl`); §3 is the exact state of chunk 2 and what is left on it.
+**2026-09-04 takeover closeout:** packet §12's final-fix implementation is
+`c4cbc1d0d` in `s4-c2-impl`, but both sequential final lenses FAIL on real
+EnvCell code/test/register defects. A further fix is round 3, so the campaign
+stop rule fired. The implementation is clean and deliberately UNLANDED; the
+campaign branch still contains S4-c1 renderer code `766f9e749`. Read packet
+§13 and this file's §3 before any stale “review then land” instruction below.
 
 ## 0. Read order
 
@@ -53,7 +55,7 @@ Scratch worktrees (detached):
 
 | Worktree | At | Purpose |
 |---|---|---|
-| `s4-c2-impl` | `cc8e5677a` (fix round 1) on `048d5b12f` (the chunk) on `766f9e749`; clean | **S4 chunk 2 lives HERE, not on the branch yet** — review the round, then land (§3) |
+| `s4-c2-impl` | `c4cbc1d0d` (final fix round) on `cc8e5677a` on `048d5b12f` on `766f9e749`; clean | **STOPPED evidence only; do not land** — packet §13 |
 | `s4-c1-impl` | `9ba8f013e` | S4-c1 baseline BINARY, built (Release App + Cli) for the landing soak A/B; keep until S4-c2 lands |
 | `s2-final-ab` | `78068b2c` | S2-final binary for same-session perf A/B (keep) |
 | `s3-review-fix` | `6575cfcee` | pre-S4 control build; stalls at the foundry login (#462) — not usable as a control |
@@ -95,9 +97,23 @@ every deviation gets a register row in the same commit.
   chamber; the zoomed-out FRONT view from the stairwell (hall arches + sky);
   #458's far-block admission (AD-118, 0.5 % edge-plane precision).
 
-## 3. S4 chunk 2 — where it stands (fix round 1 DONE, review of the round NOT started)
+## 3. S4 chunk 2 — STOPPED UNLANDED after final-round review
 
-**Two commits sit in worktree `s4-c2-impl`, NOT yet on the campaign branch:**
+**Binding current state (supersedes the historical procedure later in this
+section):** lead contract `ac74fbd84` added packet §12. Final implementation
+`c4cbc1d0d` passed its implementer matrix, then the retail lens and the
+production/gate lens both returned FAIL. The blockers are: transparent
+EnvCell subsets still draw in the opaque pass before FIFO submission; CLIP
+and detail-immediate subsets use alpha/no-depth state rather than retail's
+clip-test/depth-writing state; the tests omit the preceding opaque draw and
+pipeline descriptors; source-owned EnvCell lists are not bounded under
+capacity rejection; the 0-B tests bypass the claimed scan/filter/RHI paths;
+AP-238/AP-240 and the result note are therefore false. Packet §13 is the full
+file:line/evidence record. A code/test/register repair is a forbidden third
+round. No cherry-pick, graphical gate, or soak ran. G3/G4 remain unpassed.
+
+**Historical state before the final round (kept for audit; do not execute its
+landing procedure):**
 
 | Commit | What | State |
 |---|---|---|

docs/research/2026-09-01-overhaul/s4-depth-alpha-packet.md

@@ -720,3 +720,90 @@ change is a third round: STOP, leave the implementation unlanded, and write
 the chunk failure into the packet/ledger. Comment-only clarification that
 does not change a claim may be adjudicated by the lead; it may not conceal a
 behavior or test defect.
+
+## 13. S4-c2 final-round result — STOPPED UNLANDED (2026-09-04)
+
+**Stop rule fired.** Final-fix implementation `c4cbc1d0d` (directly on
+`cc8e5677a`, worktree `s4-c2-impl`) passed its implementer matrix, but BOTH
+sequential §12 lenses found code/test/register changes that would require a
+third fix round. Section 12 explicitly bars that round. None of
+`048d5b12f`, `cc8e5677a`, or `c4cbc1d0d` was cherry-picked to the campaign
+branch; the branch's latest renderer code remains S4-c1 `766f9e749`.
+
+### 13.1 Retail-faithful lens — FAIL
+
+Paired executable/PDB was re-confirmed (`{9e847e2f-777c-4bd9-886c-22256bb87f32}`,
+age 1). The particle row-5 fix and exact EnvCell `ConstructMesh` mask/list
+selection are correct. The following are not:
+
+1. **BLOCKING — a deferred EnvCell subset already draws at the cell turn.**
+   `WalkProductionLeafRenderer.DrawCellShell` calls `DrawOpaqueCellShells`
+   before `SubmitOrDrawTransparentCellShell`. `EnvCellRenderer`'s opaque pass
+   does not exclude a non-additive `IsTransparent` batch, so canonical pure
+   ClipMap `F4180104` / surface `08000BFF` is drawn immediately before its
+   CLIP token is appended, then drawn again at the drain. Retail row 3 only
+   appends. The new production fixture starts at dispatch and never executes
+   this preceding opaque-shell call.
+2. **MAJOR — CLIP/detail-immediate surface state is wrong.** All non-additive
+   EnvCell transparent ranges bind `_alphaPipeline` (StraightAlpha,
+   depth-write off). Retail's pure ClipMap replay uses ONE/INVSRCALPHA,
+   alpha test, and depth-write on (`SetSurface` 0x0059c6e4–0x0059c806;
+   `SetDepthBufferMode` call 0x0059c866). Detail-active row 1 uses that same
+   retail base state before its detail combine. The port also hardcodes
+   `overrideClipmap:true` although the router's ordinary mask-`0x08` row has
+   false; replay ignores the flag. Tests assert draw counts, not bound
+   pipeline/blend/depth/override state, and construct mask-`0x08` as
+   `AlphaBlend`, so the wrong state stays green.
+3. **MAJOR — register/result claims are false.** AP-238's “token granularity
+   only” statement omits premature/double draw and surface-state divergence;
+   AP-240's EnvCell “CLIP feeder” is only queue bookkeeping while the visible
+   subset has already drawn. The implementation's §12 result repeats those
+   claims.
+4. **MINOR truth:** the mesh-particle pipeline summary still says it shares
+   the billboard depth bracket despite the opaque depth-write exception; an
+   EnvCell test comment cites a nonexistent `Assert.Empty(log)`.
+
+The lens reproduced 46/46 relevant queue/particle/EnvCell/PView tests and
+42/42 particle/EnvCell renderer tests. Green tests do not contradict the
+findings because they omit the preceding opaque pass and pipeline state.
+
+### 13.2 Production/gate-honesty lens — FAIL
+
+The second lens independently confirmed both rendering blockers and added:
+
+1. **MAJOR — source scratch is not queue-bounded.** Each fixed-list
+   `EnvCellAlphaDrawSource` retains pending/prepared/draw `List<uint>`
+   buffers. Payload is reserved before queue admission; after 3,000 entries
+   `TryAppend` rejects, but the source continues growing and `Reset` only
+   clears capacity. The queue's scratch budget/capacity therefore does not
+   bound retained source memory under rejection pressure.
+2. **MAJOR — allocation evidence is vacuous for the claimed paths.** The two
+   0-B tests feed route flags directly into static dispatch with no-op sinks;
+   they do not run the production EnvCell scan/filter/RHI path, and the
+   particle test does not run `DrawImmediateParticleSubmissionRhi`.
+3. R2-3's rejected-first-use cleanup itself is correct for flush/end/abort;
+   M1, M3, and A1 have material production pins; allowed scope and
+   `git diff --check` pass.
+
+This lens reproduced Release 0 warnings/errors, 81/81 focused production
+tests, and 32/32 shader tests. Its official hermetic no-retry run was
+16,727 pass / 1 pre-existing `Console.Out` capture-race failure; isolated App
+rerun passed 6,875/6,875. InstalledDat was unavailable in that lens because
+the opt-in DAT environment was not configured. The implementer's clean-state
+evidence remains: hermetic 16,728/16,728; InstalledDat 255 pass / 10 expected
+fail / 1 skip; shaders 32/32; corrected focused 211/211. Those counts prove
+the tested behavior only; they do not repair the missing discriminators.
+
+### 13.3 Disposition
+
+- `s4-c2-impl` remains clean, detached at unlanded `c4cbc1d0d` for evidence.
+- No code fix, cherry-pick, graphical client, validation self-gate, or
+  stationary A/B was performed after the stop. The user-required graphical
+  gate is deliberately inapplicable to unlanded code.
+- A technically complete next attempt would need to fix pass membership,
+  carry exact clip/override state into an EnvCell clip/depth-writing pipeline,
+  bound source-owned payload under rejection, add end-to-end walk-leaf plus
+  pipeline-state/allocation discriminators, and rewrite AP-238/AP-240/result
+  truth. That is a THIRD fix round and is NOT authorized by this campaign
+  chunk. Resume only by an explicit owner decision that changes the process;
+  otherwise S4-c2 is stopped and G3/G4 remain unpassed.