Use a shared in-memory code store across mock, Tencent, and Aliyun SMS services so send and verify follow the same contract. Also surface batch flush failures through FlushNow and explicit error tracking hooks for audit buffering.
Add regression tests for the shipped development and SMS sample configs, and fix the SMS example to match the runtime flat Config schema instead of nested provider blocks. Verified with fresh go test runs for ./internal/config and ./internal/sms before commit.
Add the untracked SMS service package and its security-focused tests, plus database-backed IAM service unit coverage. This keeps the verification surface small and brings previously validated test/runtime support sources into version control as an isolated change.
