docs: Valhalla graduated — rename what the harness experiments on

Framing torque flagged in review on #82: the repo kept saying 'the Valhalla
lab' after #81 made production the Valhalla arm, which reifies the superseded
topology (Panama real, Valhalla experimental annex) the implementation had
just removed.

- docs/panama.md carried an objectively stale paragraph: the lab compiled with
  -source 27 --enable-preview and was 'never on the classpath the production
  tests run against', with physical separation as a structural guarantee
  against preview poisoning. All three are false now -- both arms are JDK 28,
  both load the production API, and that API is itself preview-marked.
- README's stack diagram drew 'stable-JDK implementation / Valhalla
  laboratory' as layers; replaced with JDK 28 Panama + JEP 401 production and
  representation probes.
- docs/valhalla-lab.md gains a legacy-name banner; the directory keeps its
  name for path compatibility.
- The #82 arc bullet and LATEST_STATE now name the experiment as object-model
  and layout consequence, not Valhalla.

Historical board entries are left as history.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HScwwezRdMxFfTs3WLG19d

Author: claude

.claude/board/LATEST_STATE.md

@@ -1,7 +1,7 @@
 ## 2026-09-19 — PR #81 merged (`07aa441`): production IS the Valhalla arm; Panama × Valhalla is one membrane
 
 **The frame, because it is easy to file this wrong:** this was not a JDK
-26→28 upgrade. Production was Panama-only and Valhalla lived in the lab; they
+26→28 upgrade. Production WAS Panama-only with Valhalla in a lab arm; they
 are now **one production membrane**, with JDK 28 as the enabling toolchain.
 Panama = the verb, Valhalla = the noun, **lance-graph / T0 owns storage**.
 

.claude/board/PR_ARC_INVENTORY.md

@@ -59,10 +59,15 @@
   on the wrong side of the cliff and no performance claim may be read off its
   `isValue()`. Valhalla changes what the VOCABULARY costs; it does not touch
   the membrane. No second graph representation, no row hydration introduced.
-- **Lab re-scoped, and the re-scope removed a confound it always carried:** the
-  old A/B was `(record, JDK 26)` vs `(value record, JDK 27 EA)` — two
-  variables. Both arms now run JDK 28, so the object model is the only
-  difference. Two things it forced: **preview marking is transitive** (the
+- **The harness is now a REPRESENTATION probe suite, not a "Valhalla lab" —
+  Valhalla graduated to production infrastructure and is no longer the thing
+  under test.** `valhalla-lab/` keeps its directory name for path
+  compatibility only; a doc banner says so. What it measures is object-model
+  and layout consequence: `record` vs `value record` **on one JDK, against the
+  same Valhalla-enabled production API**, with flattening and EA toggled.
+  **The re-scope also removed a confound the harness always carried:** the old
+  A/B was `(record, JDK 26)` vs `(value record, JDK 27 EA)` — two variables.
+  Both arms now run JDK 28, so the object model is the only difference. Two things it forced: **preview marking is transitive** (the
   `record` arm also runs `--enable-preview`; it is a record arm on a preview
   JVM, not a preview-free one), and **`ValueClass.isFlatArray` narrowed from
   `Object` to `Object[]`** since 27-jep401ea3, which broke the flattening probe

README.md

@@ -28,9 +28,11 @@ Rust, SoA layout, SIMD, FFM, or graph-engine internals.
                         |
              View / Mask / Lens DSL          <- lazy, monotonic-narrowing
                         |
-             stable-JDK implementation
-                        |
-               Valhalla laboratory            <- the tiny vocabulary only
+          JDK 28: Panama FFM + JEP 401         <- value-typed vocabulary,
+                        |                          production, not a lab arm
+            representation probes              <- object-model / layout
+                                                  measurements (historical
+                                                  directory: valhalla-lab/)
 
 ====================== PANAMA FFM ======================
 

docs/panama.md

@@ -80,16 +80,20 @@ remains the only thing Panama asks for. What changed is that production
 deliberately uses Valhalla value classes (JEP 401, preview on this build), so
 `--release 28 --enable-preview` is now part of the shipped build contract.
 Read every "no preview" claim below as scoped to FFM: **Panama needs no
-preview; the vocabulary types do.** The Valhalla lab
-(`valhalla-lab/src/valhalla`) is compiled *separately*, with its own
-`-source 27 --enable-preview`, into its own output directory
-(`results/valhalla-lab/`), and is never on the classpath the production
-tests or the bench harness run against. `--enable-preview`-compiled
-classfiles carry a preview marker that poisons every consumer that loads
-them; keeping the two trees physically separate (rather than, say,
-compiling once and gating features at runtime) is what makes this a
-structural guarantee rather than a discipline someone could accidentally
-violate. See `.claude/knowledge/jdk-toolchain-facts.md` for the exact
+preview; the vocabulary types do.** ⊘ **The paragraph that stood here is doubly stale and is replaced.** It said
+the lab compiles *separately* with `-source 27 --enable-preview` and is
+*"never on the classpath the production tests run against"*, and it argued
+that physical separation kept preview marking out of production. All three
+are now false: both probe arms run **JDK 28** with `-source 28 -target 28`,
+both **compile and load the production API**, and that API is itself
+preview-marked — so there is nothing to quarantine production *from*. The
+separation argument was load-bearing only while production was preview-free,
+and it stopped being that when production adopted JEP 401.
+
+The isolation that remains is ordinary and smaller: the probe harness builds
+into its own output directory and is not on the classpath of the shipped
+artifact. It is not a structural guarantee against preview poisoning, because
+preview marking is now a property of production itself. See `.claude/knowledge/jdk-toolchain-facts.md` for the exact
 verified flag matrix across all three JDKs this project touches.
 
 ## What Panama did NOT need to solve here

docs/valhalla-lab.md

@@ -1,4 +1,15 @@
-# The Valhalla lab — synthesis
+# Representation probes — synthesis
+
+> ⊘ **Legacy name.** The directory is still `valhalla-lab/` and this file is
+> still `valhalla-lab.md`, because renaming paths buys churn rather than
+> clarity. **The name no longer describes the experiment.** Valhalla is
+> production infrastructure — the six vocabulary types are `value record`s on
+> JDK 28 (PR #81) — so it is not what is being tested. What this harness
+> measures is the CONSEQUENCE of object-model and layout realizations:
+> `record` vs `value record` **on the same JDK, against the same
+> Valhalla-enabled production API**, with flattening and escape analysis
+> toggled. Read every "Valhalla arm" below as "value-record arm", and never as
+> evidence that production is fundamentally Panama with Valhalla bolted on.
 
 > Companion to `valhalla-lab/README.md` and `valhalla-lab/docs/three-truths.md`
 > (the raw findings and numbers) and `.claude/knowledge/valhalla-three-truths-method.md`