S00-011: Verify public npm access and exact-version tarball integrity

Changes: Add a scoped fresh-cache registry probe, safe reproduction instructions and artifact ignore rule; record actual TLS-enabled metadata/download results and review handoff without selecting a stack or changing the harness.
Validation: Original npm view command and verify.py returned exit 0; react@19.3.1 tarball (26394 bytes) matched registry SHA-512. make check passed validation and 66 tooling tests. git diff --check passed. App install/build and different-harness connectivity remain unverified.

Task: S00-011
Agent: auto-ci-cd-d105e8027730
Role: ci-cd
Action: claim
Status: review

Task title: Restore verified npm registry access for the stack spike

experiments/0001-stack/registry-access/README.md

@@ -0,0 +1,79 @@
+# Verified public npm registry path — S00-011
+
+Input: S00-002 failed to resolve registry.npmjs.org. Output: a repeatable public
+metadata and exact-version tarball probe in the current executor harness.
+This is connectivity evidence, not a framework choice or an application build.
+
+## Execution environment and reproduction
+
+Verified in the fresh auto-ci-cd-d105e8027730 executor on 2026-10-15:
+Node v26.3.0, npm 11.16.0, Python 3, macOS paths. These are observed tools,
+not accepted project runtime versions. The supplied harness has network access
+enabled, workspace-write sandboxing and approval policy never. No harness,
+runner, DNS, proxy, certificate or Git configuration was changed by this task.
+The initial working tree contained only the coordinator's state/tasks.json claim.
+
+The next fresh executor must retain network-enabled execution, working DNS and
+HTTPS egress to registry.npmjs.org:443, normal certificate trust, and project-only
+source writes with temporary writes under /private/tmp. No credentials are needed.
+Do not disable TLS or relax the write sandbox. The previous DNS failure was not
+reproduced here; its external correction mechanism is unknown. This report does
+not promise network availability in a different or future harness.
+
+From the project root:
+
+```sh
+npm view react version license engines --json --cache /private/tmp/luma-stack-npm-cache --fetch-retries=0 --fetch-timeout=15000
+python3 experiments/0001-stack/registry-access/verify.py
+```
+
+The first command exactly repeats the original failure. It returned exit 0:
+
+```json
+{"version":"19.3.1","license":"MIT","engines":{"node":">=0.10.0"}}
+```
+
+`npm config get strict-ssl` returned `true` (exit 0). The second command uses a
+new TemporaryDirectory under /private/tmp with empty user/global npmrc files
+and a fresh cache, runs from there to avoid project npmrc, and removes that
+temporary directory after execution. It refuses NODE_TLS_REJECT_UNAUTHORIZED=0.
+It invokes these argument arrays via subprocess, without a shell:
+
+```text
+npm view react@19.3.1 version license engines dist --json <common-options>
+npm pack react@19.3.1 --ignore-scripts --json --pack-destination=<absolute-scope>/artifacts <common-options>
+```
+
+The exact common options are:
+
+```text
+--registry=https://registry.npmjs.org/ --strict-ssl=true
+--fetch-retries=0 --fetch-timeout=15000
+--cache=<fresh-temp>/cache --userconfig=<fresh-temp>/user.npmrc
+--globalconfig=<fresh-temp>/global.npmrc
+```
+
+The probe installs no dependencies, extracts no archive, runs no package scripts
+and adds no package manifest/lockfile. React is only a public connectivity sample.
+It checks the metadata version and exact HTTPS tarball URL, downloads through
+npm, and independently compares Python hashlib SHA-512/base64 with dist.integrity
+and npm pack's integrity. It uses standard libraries, not custom cryptography.
+Errors/mismatches exit nonzero. Do not print private environment/configuration.
+
+## Actual result
+
+Both child npm commands and verify.py returned exit 0, using the fresh cache:
+
+- Package: react@19.3.1; metadata license MIT.
+- URL: https://registry.npmjs.org/react/-/react-19.3.1.tgz
+- Retrieved size: 26394 bytes.
+- Registry and independently computed integrity:
+  `sha512-QNhWdt7nrgVWWQG58QuGsAR3jv3Hbe4mb4vz7w2csnHavciZJgda1CPNaldF6eVxv90ud3jUXpKlHL69gO38yw==`
+
+The local `artifacts/` directory contains the tarball, public metadata.json and
+result.json; it is deliberately ignored by Git. Rerun the probe for independent
+review instead of trusting an archived result. No secrets are recorded. Registry
+signature/provenance verification is not claimed; the acceptance check is registry
+integrity over verified HTTPS. Browser/CORS, dependency install, build, framework
+compatibility and license acceptance remain outside this task. S00-002 must run
+its own clean install/build and make its own stack/runtime decision after review.