## Summary
Selective migration to the managed Spec Kit project structure.
## Included
- add managed Spec Kit integration metadata under `.specify/`
- add bundled `speckit` workflow registry
- add bundled `git` extension, scripts, and config
- add new `speckit.git.*` command surfaces for Copilot, Gemini, and `.agents`
- add the Spec Kit plan marker block to `.github/copilot-instructions.md`
## Intentionally excluded
- no replacement of the existing customized core `speckit.*.agent.md` files
- no `.vscode/settings.json` commit; the copied manifest was adjusted accordingly
- no changes to the active `specs/231-finding-outcome-taxonomy` work
## Validation
- `specify integration list`
- `specify workflow list`
- `specify extension list`
- focused managed-file diff review
Co-authored-by: Ahmed Darrazi <ahmed.darrazi@live.de>
Reviewed-on: #266
