Migrate coupled provider selectors as one validated unit

When a runtime composes one provider for detection and another for transcription, treat their selectors as a single configuration unit. Copying only one selector can produce an unsupported pair that fails startup even though every endpoint and credential is valid. Read the target's compatibility validation, compare the complete selector tuple with the known-good environment, stage all related values without deploying, and then roll once. Keep the prior tuple available for rollback.

Applies when: a service validates combinations of two or more provider or mode selectors. Keywords: provider selector pair startup validation atomic deploy rollback configuration