## Summary
- add the implementation-ready spec-prep artifacts for Spec 280: Filament Workspace Tenancy & Environment Routing Cutover
- define the bounded scope, rollout constraints, route contract, and validation plan for the workspace-first routing cutover
- update the generated Copilot agent context for the active feature branch
## Testing
- not run; this branch adds spec-prep artifacts only and does not change application code
## Notes
- no application runtime, database, or frontend code changes are included in this PR
- target base branch requested: `platform-dev`
Co-authored-by: Ahmed Darrazi <ahmed.darrazi@live.de>
Reviewed-on: #336
