Summary

• start in the editor when no saved workspace or project can be restored
• keep manually opened Project Library sessions dismissible
• distinguish optional browsing from the required project choice after deleting the active saved project
• return to the editor when optional New Project or Guided Drawing setup is canceled
• leave onboarding redesign for a later slice

Verification

• npm run test:run (88 files, 486 tests)
• npm run lint -- --quiet
• npm run build
• npx fallow audit --changed-since origin/develop
• git diff --check
• live local-app startup smoke check with no new console errors

Closes #320