Update and finalize the next stages of the implementation roadmap

docs/policy/development.md

@@ -158,6 +158,18 @@ Test close to the behavior being changed:
 - Use `internal/testutil` for shared valid fixtures only; keep edge cases near the package under test.
 - Run `go test ./...` after cross-package changes or documentation/example changes tied to tests.
 
+Live integration tests must be opt-in and skipped during normal `go test ./...`
+unless their required environment variables are set. Test-only environment
+variables must use this prefix shape:
+
+```text
+DISTRIBUTOR_TEST_<BACKEND>_*
+```
+
+Examples include `DISTRIBUTOR_TEST_SSH_HOST` and
+`DISTRIBUTOR_TEST_S3_ENDPOINT`. Do not use production credential variable names
+for test-only controls.
+
 ## Examples
 
 Examples under `examples/` must be valid, maintained, and free of secrets.