Return explicit errors from AlertAPI construction instead of panicking inside the library layer, and let main own process-level failure handling.
Also delete the unused config.MustLoad helper and lock the supported config loading paths with tests.
Add broader e2e coverage for account, package, billing, tracing, and reliability scenarios.\nSupport Unix socket DSN formatting in config and cover it with unit tests.\nIgnore local assistant metadata and generated gate artifacts to reduce workspace noise.
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.