workstation-v0: add revert mode to shell/fish autopatch + CI revert tests

[mdheller]

Adds operational symmetry and stronger test coverage to the workstation-v0 autopatch helpers.

Changes:

• profiles/linux-dev/workstation-v0/bin/patch-shell.sh
  • add revert mode that removes the bounded marker block
• profiles/linux-dev/workstation-v0/bin/patch-fish.sh
  • add revert mode that removes the bounded marker block
  • add SOURCEOS_FISH_CONFIG override for CI/testability
• .github/workflows/workstation-scripts.yml
  • add patch-shell revert smoke test
  • add patch-fish apply/revert smoke test
• docs/workstation/RUNBOOK.md
  • document revert usage for both helpers

Why:

• The autopatch flow should be reversible, not just idempotent.
• CI should validate both application and removal of the patch blocks.

Scope note:

• This PR improves the helper scripts and CI first.
• Exposing revert through sourceos fix ... can follow if desired.