docs(overhaul): authorize five S4-c2 completion attempts

Start attempt 1/5 as an evidence-and-comment-only repair of a094bf2b7. Preserve behavior, assertions, shader/SPIR-V, register, package, sequential review, and no-landing-before-dual-PASS constraints.

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

@@ -97,21 +97,18 @@ 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 — owner-authorized repair STOPPED, still UNLANDED
+## 3. S4 chunk 2 — owner attempt 1/5 ACTIVE, still UNLANDED
 
 **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 both lenses failed for the
-defects recorded in packet §13. The owner explicitly authorized one repair;
-packet §14 is its bounded contract and lead commit `a094bf2b7` is the clean,
-unlanded evidence in `s4-c2-impl`. The retail lens found the renderer behavior
-correct but returned FAIL on the binding evidence/prose contract: the commit
-body did not enumerate all 14 mutation failures; one packet mutation names the
-wrong first assertion; one paired-binary address and four source/test comments
-are stale. Exact findings are packet §15. The production lens was not started.
-Because §14 grants no implicit fourth repair, no chunk commit was landed or
-graphically gated. The campaign renderer remains S4-c1 `766f9e749`; G3/G4
-remain unpassed. Resume only by another explicit owner process decision.
+section):** clean unlanded implementation `a094bf2b7` is behaviorally
+retail-faithful but failed its first review on the evidence/prose findings in
+packet §15. The owner has now authorized up to five more attempts. Packet §16
+is binding; attempt 1/5 corrects only the exact address, mutation-first-failure
+record, three source comments, one test comment, and the commit body. The
+implementation agent returns an uncommitted diff; the lead verifies and amends
+the unlanded commit, then runs retail followed by production/gate review.
+Nothing lands or graphically gates before dual PASS. The campaign renderer
+remains S4-c1 `766f9e749`; G3/G4 remain unpassed.
 
 **Historical state before the final round (kept for audit; do not execute its
 landing procedure):**

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

@@ -1015,3 +1015,58 @@ would be a post-review fourth repair. §14 explicitly grants no implicit fourth
 round, so the implementation remains unlanded, the campaign renderer remains
 S4-c1 `766f9e749`, and G3/G4 remain unpassed. Resume only by another explicit
 owner process decision.
+
+## 16. Owner-authorized evidence/prose repair budget (2026-09-04)
+
+The owner replied: “Ok but fix those and finish these. You can try 5 more
+times.” This explicitly authorizes up to five additional bounded
+implementation-plus-sequential-review attempts for S4-c2. It does not weaken
+the retail/binary verification, dual-review, landing, graphical-gate, ledger,
+or no-merge-before-G4 rules. Attempt 1/5 starts from clean unlanded
+`a094bf2b77c3061288185f069fa0b5e494ee8540`; the campaign branch remains on
+S4-c1 until a complete attempt receives retail PASS followed by production/
+gate PASS.
+
+### 16.1 Attempt 1/5 contract — evidence and comment truth only
+
+Make exactly the retail lens's §15 corrections; no renderer behavior, shader
+instruction, SPIR-V, test assertion, register row, package model, or gate is
+weakened or changed:
+
+1. In the §12 result, attribute `SetAlphaTestEnable` to `0x0059c821` and
+   `SetAlphaTestFunction(GREATER_EQUAL)` to `0x0059c838`.
+2. Correct mutation 5's actual first failure: after `<` becomes `<=`, the
+   preceding `Assert.Contains("if (color.a < alphaCutoff) discard;")` fails
+   because the required source spelling is absent. Do not claim the later
+   `Assert.DoesNotContain` is first.
+3. Update `mesh_detail.vert`: exact `uParamB=1` selects the building/object
+   category; EnvCell zero and CLIP 100/255 or 200/255 select the bound
+   environment category, and the fragment shader consumes the CLIP values.
+4. Update `EnvCellRenderer.Rhi.cs`: the opaque environment-detail replay is
+   for the already-filtered opaque shell commands; transparent ClipMap is
+   excluded and takes its immediate/delayed CLIP path with its own detail
+   contribution.
+5. Update `ParticleRenderer.Rhi.cs` from “five pipelines” to the exact six.
+6. Update `RetailAlphaMeshRouterTests.cs`: ordinary Wb reconstruction still
+   owns AP-239, while mesh particles genuinely call
+   `MaskFromTranslucencyKind`; do not claim production never calls it.
+7. The lead amends the unlanded implementation commit so its body names all
+   fourteen owner-repair mutations and each actual first failing assertion,
+   using the corrected mutation-5 ordering above. The implementation agent
+   returns an uncommitted diff and does not amend or commit.
+
+Allowed implementation files are only the four source/test files named above
+plus this packet (five files total). `git diff --check`, Release build, the
+exact focused source/comment
+and behavioral tests, shader/manifest tests, and the two real 0-B allocation
+pins must remain green. The unchanged 16,735/16,735 hermetic and 255/10/1
+InstalledDat evidence may be reused only if the diff remains prose-only;
+otherwise rerun the affected complete lane. No graphical client runs from an
+implementation/review worktree.
+
+Review attempt 1 sequentially: retail/evidence lens first, then production/
+gate lens only on PASS. A finding consumes attempt 1 and returns to the lead,
+who writes the next bounded contract against that exact finding; up to four
+further attempts remain. Dual PASS authorizes landing the full S4-c2 stack,
+fresh campaign Release/hermetic/InstalledDat gates, then the graphical and
+stationary-soak gates. G3/G4 remain unpassed until those steps finish.