Expand the workstation showcase

[priithunt]

Summary

• broaden the public tour to mail, calendar, Concord, shell, Git, package ownership, synchronization, backup, and lifecycle workflows
• add deterministic plugin pins, community files, and a documented one-way publication process
• harden the verifier for exact inventory, syntax, file modes, links, and sensitive-looking content

Safety and verification

• The change contains no account, address, endpoint, device ID, credential, or private key.
• New and removed files are reflected in manifest.json.
• The final snapshot was rendered from the curated private source.
• The private targeted showcase fixture passed during guarded publication.
• Relevant documentation is updated.