G-172: correct the zig-gate rebuild-blocker claim; Approach 6 -> in-situ; r2 family + tools republished at baseline floor

The drafting session recorded the recipes' required_zig gate as blocking any
rebuild on this box (a prerelease sorts below 0.16.0; "newest zig otherwise
present is 0.15.2"). Wrong: only the stray dev copy is rejected - the zigpin
toolchain bin/tools/zig-x86_64-windows-0.16.0/zig.exe is a released 0.16.0,
present and passing the gate (the zig-x86_64-windows-* naming family in
bin/tools was missed and a removal back-inferred from the artifact records).
Notes bullet and Progress corrected; nothing was removed and nothing blocks.

Approach 6 rewritten per user decision: republication is in-situ replacement
under existing artifact names/revisions - punkbin immutability deliberately
violable during alpha (all consumers in-house, zero third-party users).

Progress: Approach 6 executed for the r2 generation + tools (punkbin ab5611d
pushed) - full bootstrap rebuild with the pinned zig, zmm=0 ymm=0 audits on
all five binaries, family_check PASS, two consecutive core-gate PASS runs
with identical totals (interp-36.7 bgerror-race jitter and a 4h
httpProxy.test ThreadLevel-1 hang documented). Record-honesty residual noted:
published tomls carry emission-time [tests] summaries - refresh folded into
Approach 3. Remaining: floor field, audit tool, punk-runtime surfacing; r1
disposition + bin/punk9* kit rebake behind those.

goals_lint: clean (81 active, 91 archived).

Claude-Session: https://claude.ai/code/session_01WXribLxUjk3dZUsN3r6rKb
Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com

goals/G-172-distributed-binary-cpu-floor.md

@@ -41,7 +41,7 @@ Confirmed against the reporting fleet - the split is exactly the AVX-512 line:
 Cause: the recipes called `b.standardTargetOptions(.{})` and no build path
 passed `-Dtarget`/`-Dcpu`. With no flag, zig resolves cpu_model
 `determined_by_arch_os` by NATIVE detection; on a Zen 5 host that is `znver5`,
-and `ReleaseFast` then auto-vectorises freely. Measured with the pinned zig on
+and `ReleaseFast` then auto-vectorises freely. Measured with the bundled 0.16.0-dev zig on
 an auto-vectorisable C loop: flagless -> `znver5`, zmm=805; `-Dcpu=native` ->
 `znver5`, zmm=805; `-Dtarget=x86_64-windows` -> `x86_64`, zmm=0;
 `-Dcpu=baseline` -> `x86_64`, zmm=0; `-Dcpu=x86_64_v2` -> `x86_64_v2`, zmm=0.
@@ -98,9 +98,17 @@ project's first contact with a new user fails with no message at all.
    binaries are not runnable here"), so that is where a floor the host does not
    meet becomes a named diagnosis. `list` annotates rows the local CPU cannot
    run.
-6. Republication of the affected artifacts as a new revision, and repointing
+6. Republication is IN-SITU replacement (user decision 2026-08-06): rebuilt
-   punkbin `defaults.txt`, is the closing step - sequenced after 1-5 so the
+   binaries replace the unsuitable artifacts under their existing names and
-   rebuilt family is audited and self-describing before it becomes the default.
+   revisions, with sidecar tomls and `sha1sums.txt` regenerated to match.
+   Artifact immutability remains the long-term intention but is explicitly
+   violable during alpha - every consuming system is in-house, there are no
+   third-party users, and leaving known-dead binaries fetchable is the worse
+   outcome. No `defaults.txt` repoint is needed (it already names
+   `tclsh9.0.5-punk-r2.exe`). Replacement may proceed as soon as a rebuilt
+   binary passes the zmm audit; if the floor field (Approach 3) is not yet in
+   the record schema, a second in-situ record refresh adds it later - cheap
+   under the same dispensation.
 
 ## Alternatives considered
 
@@ -147,12 +155,19 @@ project's first contact with a new user fails with no message at all.
   bin/punkzip.exe bin/punkres.exe`): surveyed and judged not related in
   substance - G-110 (shared-lib extraction cache), G-131 (boot payload
   autodetection), G-141, G-157, G-158 (bin/ sibling-file matches only).
-- Deliberately outside this contract: all four recipes gate on
+- Zig version gate (corrected 2026-08-06 - an earlier note here claimed the
-  `required_zig = "0.16.0"` with a `.lt` SemanticVersion compare, so a
+  gate blocks rebuilding on this box; it does not): the recipes' SemVer gate
-  prerelease toolchain (`0.16.0-dev.254+6dd0270a1`, the copy under bin/tools)
+  does reject the stray prerelease copy under
-  sorts below the pin and is rejected by the recipes' own gate. A real defect
+  `bin/tools/zig-0.16.0-dev.254+6dd0270a1/` (a prerelease sorts below its
-  in the same lines, but a different one - it blocks rebuilding here until a
+  release), but that copy is not the pinned toolchain. The `zigpin` record
-  released 0.16.0 is materialized.
+  (`sources.config`) points at `bin/tools/zig-x86_64-windows-0.16.0/zig.exe`,
+  a released 0.16.0 that is present, reports `0.16.0`, and passes the gate;
+  `suite.tcl` and the README both resolve to it by default. The removed-zig
+  claim arose from missing the `zig-x86_64-windows-*` naming family in
+  `bin/tools/` and back-inferring a removal from the artifact records.
+  Rejecting a 0.16.0-dev snapshot is arguably correct behavior besides - it
+  predates the 0.16 API the recipes are written against - so nothing here
+  blocks or needs fixing.
 - Verification note: `llvm-objdump -d --section=.text <exe>` counting
   `zmm[0-9]` operands is the quick manual check used throughout the Context
   measurements. Linear disassembly of a non-AVX-512 binary yields ~3 false
@@ -169,9 +184,39 @@ project's first contact with a new user fails with no message at all.
   by `zig ast-check` on all four; the mechanism verified separately with the
   same toolchain and optimize level on an equivalent recipe (flagless ->
   baseline/zmm=0, `-Dcpu=native` -> znver5/zmm=805). A full suite build was NOT
-  run - blocked by the version-gate defect noted above. The `b.graph.host`
+  run in that session - recorded at the time as gate-blocked, corrected in the
+  next entry (the pinned toolchain passes the gate). The `b.graph.host`
   target sites elsewhere in these recipes are build-time helper tools that are
   never distributed and are correct as native.
-- Remaining for acceptance: Approach 3 (floor in the artifact record), 4 (audit
+- 2026-08-06 (correction, later session): the gate-blocker claim is wrong -
-  tool + fixture), 5 (punk-runtime surfacing and the use/run verdict), 6
+  the pinned toolchain `bin/tools/zig-x86_64-windows-0.16.0/zig.exe` (the
-  (rebuild, republish, repoint `defaults.txt`).
+  `zigpin` record) is a released 0.16.0, present on this box and passing the
+  recipes' gate; only the stray dev copy is rejected. Notes bullet rewritten
+  accordingly. Nothing blocks the rebuild here.
+- 2026-08-06: user decision - republication is in-situ replacement under the
+  existing artifact names/revisions (Approach 6 rewritten); punkbin
+  immutability is deliberately violable during alpha with zero third-party
+  consumers. Disposition of the r1-generation artifacts (replace vs drop)
+  remains a pending curation call.
+- 2026-08-06 (later session): Approach 6 executed for the r2 generation +
+  tools. Full `zig build bootstrap` with the pinned released 0.16.0 rebuilt
+  the family at the baseline floor: all three r2 exes audit zmm=0 ymm=0 (was
+  2756/617), family_check self-contained PASS, punk-r2 build_id unchanged.
+  punkzip 2.4.0 / punkres 0.3.1 rebuilt (zmm 1724/1423 -> 0), own suites
+  pass; local bin/ copies replaced. Core test-gate: two consecutive PASS runs
+  against the dispositioned baseline (69552 run / 8 failed, identical totals
+  both runs; a first attempt failed once on interp-36.7, a bgerror timing
+  race - passed on both reruns; one intermediate run hung 4h inside
+  httpProxy.test "ThreadLevel 1", the socket-flake class - killed and rerun).
+  lib tier audited clean (tcllibc.dll zmm=0; the critcl -target pin already
+  protected it). Published in-situ: punkbin ab5611d (3 exes + 3 schema-2
+  tomls + 2 versioned tool exes + both sha1sums.txt), pushed to
+  origin/master. Record-honesty residual: the published tomls' [tests] lines
+  carry the emission-time (July) summaries; the fresh shipped-codegen gate
+  evidence lives in _build testreports - fold a [tests] refresh into the
+  Approach 3 record work.
+- Remaining for acceptance: Approach 3 (floor in the artifact record, folding
+  in a [tests]-freshness refresh of the replaced tomls), 4 (audit tool +
+  fixture), 5 (punk-runtime surfacing and the use/run verdict). Behind those:
+  r1-generation disposition (replace vs drop) and the bin/ punk9* kit rebake
+  with the new runtime (punkproject version-gate discipline applies).