feat: add typed SMS configuration flow

[Zetazzz]

Summary

• add extensible string-based SMS provider configuration to @constructive-io/graphql-types
• parse SMS_* and DEVSMS_* environment variables in @constructive-io/graphql-env using shared 12factor-env coercion
• preserve the existing defaults → config → environment → runtime override precedence
• add a typed SEND_SMS_DRY_RUN switch for non-delivery validation

Validation

• pnpm --dir graphql/env test -- __tests__/merge.test.ts --runInBand (9/9 passed)
• pnpm --dir graphql/env build
• pnpm --dir graphql/types build
• pnpm --dir packages/12factor-env exec jest --runInBand (29/29 passed)
• git diff --check
• post-rebase full CI (build, unit, PG, integration, and AI matrices passed)

Cross-repository flow

This is the Constructive configuration layer for the new SMS verification-code flow.

• companion implementation: feat: add SMS verification code flow constructive-functions#113
• cross-repository E2E bridge: constructive-io/constructive-hub#580