spec: add admin surface scope shell context audit (#373)
## Summary
- add Spec 318 audit artifacts for admin surface scope and shell context consistency after Specs 314-317
- document browser-backed findings for workspace hubs, environment-scoped pages, filtered workspace hubs, and mismatch cases
- capture recommended follow-up specs for baseline compare, baseline ownership, alerts/audit filter contracts, classifier regression coverage, and sidebar scope declarations
## Testing
- not run; analysis-only spec artifacts with no runtime or test code changes
Co-authored-by: Ahmed Darrazi <ahmed.darrazi@live.de>
Reviewed-on: #373