Verify restored pinned Linux XMPP environment access

Changes: Add the S00-024 continuation checkpoint, refresh verified runtime/cache paths, and replace the blocked handoff with QA and S00-020 restart instructions.
Validation: Existing verify.py passed official HTTPS/checksum retrieval, Node 24.21.0/npm 11.19.0, fresh-cache locked npm ci and Stanza import. Independent archive/input/version/config assertions, tasks.py validate and diff/scope/whitespace checks passed. Browser/WSS and product readiness remain unverified.
