S00-020: Verify pinned Linux XMPP toolchain restoration

Changes: Refresh the environment-access result and document S00-020 restoration, accepted prerequisites and independent QA handoff; preserve probe code and parent dependency graph.
Validation: verify.py passed official HTTPS vendor checksum, Node 24.21.0/npm 11.19.0, fresh-cache strict npm ci and Stanza import. Separate artifact/input/version/strict-setting assertions and tasks.py validate passed. No browser/WSS or product readiness check performed.

Task: S00-020
Agent: auto-ci-cd-2a0186c54ce9
Role: ci-cd
Action: claim
Status: review

Task title: Restore access to the pinned Linux XMPP experiment toolchain

experiments/0002-xmpp-library/environment-access/README.md

@@ -1,4 +1,4 @@
-# S00-026 Linux environment access probe
+# S00-020 Linux environment access probe
 
 Normal configured HTTPS access, authorized by the assigned environment-access
 probe and this session's enabled network, succeeded on 2026-10-15. The previous
@@ -40,9 +40,9 @@ license files; dependency notices remain in the existing experiment inventories.
 
 Checksum verification trusts the vendor HTTPS origin; no detached signature,
 package provenance/advisory audit, browser/WSS authentication, application build
-or interoperability claim is made. This outcome is submitted for independent
-QA review only. S00-020, S00-024 and S00-003 remain unfinished; this executor
-does not continue their work or change their statuses directly.
+or interoperability claim is made. The S00-026 access prerequisite and S00-024 continuation checkpoint are now
+independently accepted. S00-020 is submitted for its own independent QA review;
+S00-003 remains separate unfinished work. Historical checkpoints follow.
 
 ## S00-024 continuation checkpoint
 
@@ -59,3 +59,23 @@ command above, verify result.json and use its runtime_bin with an isolated cache
 within its own card. Host Node/npm are not the pinned runtime. Temporary paths
 can expire. This checkpoint does not install dependencies into the parent
 experiment or complete S00-020/S00-003; their own acceptance remains required.
+
+## S00-020 environment restoration result
+
+On 2026-10-15 executor auto-ci-cd-2a0186c54ce9 repeated the reviewed probe in
+this fresh assigned session. Official checksum/archive HTTPS retrieval succeeded
+through the existing configured route. Vendor SHA256 matched before extraction;
+Linux Node v24.21.0/npm 11.19.0 executed, fresh-cache npm ci installed all eight
+unchanged parent locked dependencies and Stanza 12.22.1 createClient imported.
+Separate assertions rechecked downloaded artifacts, copied input hashes, every
+installed version and effective strict TLS/engine/script settings. No probe code,
+parent manifest/lock, stack, specs or network/system configuration changed.
+
+See state/evidence/S00-020-auto-ci-cd-2a0186c54ce9.md and the current result.json.
+QA must rerun verify.py with fresh retrieval and inspect scope before accepting
+S00-020. After its reviewed acceptance the coordinator may assign S00-003 to a
+fresh executor. That executor can use result.json runtime_bin for pinned tools;
+the verified Stanza installation is confined here, not in the parent experiment.
+The parent task must perform its own scoped dependency installation and WSS/
+authentication checks. Temporary paths may expire; rerun the probe if needed.
+No browser, WSS, application readiness or interoperability result is supplied.

experiments/0002-xmpp-library/environment-access/result.json

@@ -7,8 +7,8 @@
     "node": "v24.21.0",
     "npm": "11.19.0"
   },
-  "runtime_bin": "/tmp/luma-S00-026-mil9mnes/node-v24.21.0-linux-x64/bin",
-  "cache": "/tmp/luma-S00-026-mil9mnes/npm-cache",
+  "runtime_bin": "/tmp/luma-S00-026-g156ah2_/node-v24.21.0-linux-x64/bin",
+  "cache": "/tmp/luma-S00-026-g156ah2_/npm-cache",
   "parent_sha256": {
     "package.json": "e0ffb0c94e198e26f8e44e9b22ff4e121760d9f1197ed7bd5a90e1b4bb112766",
     "package-lock.json": "9c85ad62721eb2deacb298f29fa2bae211a29c964707d52c2dfbf8614b7dbb05"