docs: Fystash as experimental Harbor cloud env (-e fystash)

[fystash]

Summary

Adds a short Fystash subsection to docs/v1/harbor.md so Verifiers HarborTaskset users can point Harbor at warm Firecracker rooms via -e fystash.

• Links the open Harbor provider PR: Add Fystash cloud sandbox provider (--env fystash) harbor-framework/harbor#2491
• Partner how-to: https://docs.fystash.ai/guides/verifiers
• Honesty: experimental until Harbor merge; not Environments Hub; not a Prime Sandboxes SDK plugin

Why

Verifiers already routes Harbor tasksets through Harbor’s pluggable environments. Fystash is landing as a Harbor cloud sandbox (same surface as Daytona/Modal). This docs note makes that path discoverable without claiming Environments Hub listing.

Test plan

• Docs render on ReadTheDocs / local docs build
• Links resolve
• Optional: after Harbor merge, smoke harbor run … -e fystash under a HarborTaskset

Made with Cursor

Note

Document Fystash as an experimental Harbor cloud environment (-e fystash)

Adds a new 'Fystash cloud sandboxes (experimental)' section to harbor.md covering environment variable setup (FYSTASH_API, FYSTASH_API_KEY, optional FYSTASH_TEMPLATE_ID), an example harbor run command, and a link to the upstream Harbor provider PR. Includes disclaimers that Fystash is experimental and not part of the Prime Sandboxes SDK or Environments Hub.

^{Macroscope summarized a07594a.}