- Add testseam.Protect for save-and-restore seams with no up-front stub
value (e.g. os.Args mutated by the code under test).
- Migrate all 35 remaining manual prev/assign/t.Cleanup-restore trios to
testseam.Swap/Protect across app, auth, cli, event, helpers, output,
pipeline, and shortcut tests; restores can no longer be forgotten.
- check-schema-catalog.sh: fail closed when a manual seam restore
reappears in any *_test.go (internal/testseam exempt).
Seam injection is now a mechanism, not a convention.